As preparation, I reviewed several pro games with an eye to when strong looking groups get sacrified or bullied. Ke Jie vs. Chen Yaoye (2017-07-05) was fascinating. While it doesn't get sacrified, White had a strong looking group (3-4 point high approach, inside contact joseki) gets chased into the center.

I'm hesitant to comment on pro games, but I think that playing that close to the edge is less common for people at my level.

I considered playing the first move as a king, but couldn't convince myself that it was worthwhile.

This has been my standard opening as white against lately, and I don't see any reason to deviate from that here. I like both playing a 3-4 stone and the opportunity for a cross fuseki.

In general, my strategy will be to play a thick and/or territorial game early on. As soon as I know that a stone or group can live without being harassed for profit by black, I can begin adding kings to a group. Since a lot of pros have been experimenting with an early 3-3 invasion after the AlphaGo games and I know a 3-3 invasion can't be killed, I will be aiming to try invading with a king as early as it seems reasonable. I'd rather do this early in the game anyway before there's the possibility of ko developing in a crucial position on the board, because every move in that corner will demand an immediate response. If an early 3-3 invasion is already considered good and I can add kings to it right away, it seems that this would tip the balance in the invader's favor. If black plays a king on his wall, I can make potentially make sente moves to reduce the use of his outside thickness while taking profit elsewhere. This does mean that I can't leave the position unsettled as AlphaGo often does, but I think the slightly increased profit will make up for that.

Some additional thoughts:
I know that my move is considered questionable because black can play the lower left 4-4 and then the approach is good for black if white takes the other corner. I don't think the difference is huge though (move 2 will not be what loses this game, despite Kajiwara's musings!), and I still like getting the 3-4 stone down early. Perhaps I'll reconsider when I get stronger.

I don't think this is questionable. If you were facing the black stone, then it's not recommended (direction of play/basics). But since it's facing an empty corner, it's fine, and cross fuseki tends to favor white with komi. Additionally, if black does take the other corner, that places the 3-4 stone better in a territorial standpoint than the 4-4, and cross fuseki is usually more territorial.

I agree that the other 3-4 is more questionable (that's the one Kajiwara specifically mentioned), but when I went to look for fuseki that used this I found a sensei's library page that claimed black had a 65% winning percentage in pro games after this move and playing the other 4-4 point in the lower left. It's still played, though, so I don't think it's too bad. And I don't think it will make a big difference at this level, especially since I want to avoid allowing a 3-3 invasion for the same reasons I mentioned above.

Sensei's library calls this the Showa fuseki. I've been wanting to study Go Seigen some more, so a return to that era seems appropriate.

I still think the 3-3 invasion has added value in this variant, so I don't want to play my normal move at the 4-4. I assume black will approach next. There are lots of variants after that, but in all of them I should be able to keep his groups unsettled for a while so he can't immediately play a king and gain an advantage.

Actually, the Showa fuseki is if black makes a high approach to one of my 3-4 stones.

no kings played yet. Actually I might have played a king on 4-4 or 3-4, I wouldnt intend to sacrifice that.
As for Jeromies idea of invading 3-3 with a king, I dont like it. It just has a problem if black plays a double hane. Yes you will live, but you end up with a pretty bad sequence if you cant give your corner up:

Click Here To Show Diagram Code

[go]$$W .
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . 8 7 9 . . |
$$ | . . . O . . . . . . . . . . . 2 1 . . |
$$ | . . . , . . . . . , . . . . . X 3 . . |
$$ | . . . . . . . . . . . . . . . 0 4 5 . |
$$ | . . . . . . . . . . . . . . . . . 6 . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . X . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

This seems to be the best thing you get if 1 and 3 were kings, even worse, if 5 is also a king.
Now ok, assume you played 1,3,7,9 as kings in this sequence, so that gained you 4 points compared to not playing kings. But even if 1 and 3 were not kings, depending on the choice of variantion, you might start putting kings starting with 7, so the gain is between 2 and 4 points. I dont think thats worth it, but not 100% sure.

Interesting.

According to Waltheri's pattern matching, it does increase black's ratio to 55-58%, however that's for all games. If you only search modern games, then it maintains a 50% ratio. That's for pros. At our level, yeah, I don't think it's a big deal either. Next time, black hole fuseki!

http://ps.waltheri.net/

Click Here To Show Diagram Code

[go]$$c .
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 2 . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . 1 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . d . . . . . . . . . . . . . . . |
$$ | . . b c . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . a 5 . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . 3 . . . |
$$ | . . . 4 . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

I considered a, b, c, and d.

There are two basic choices here: settle a group quickly so I can add king stones or leave things unsettled so no one can add king stones.

My initial instinct was to play a pincer and leave things unsettled, but I don't think that works as well with the 3-4 point up top as I would like. It's certainly playable (all three pincers appear with approximately equal frequency on ps.waltheri.net), but the move I chose could lead to some solid territory and the chance to settle quickly. That also seems to be the most common choice on ps.waltheri.net. This is also consistent with my decision to play a territorial / thick game.

I can't quite play a king yet, but if I get to play the standard draw back joseki after a hane on the outside, I think I could add one to this group.

I assume both of them have already figured out some basics about the kings.
(a) a king: no throw-in ;
(b) a king: not in a ko shape ( unless you're 100% sure you win the ko right now ) ;
(c) the final move to make your own group 100% alive should be a king ;
( Barring (a) and (b). Any other exceptions to this ? )
Example:

Click Here To Show Diagram Code

[go]$$
$$ ---------------
$$ | . B . X O . .
$$ | X X X X O . .
$$ | O O O O O . .
$$ | . . . , . . .
$$ | . . . . . . .
$$[/go]

(d) kings in nakade: case by case ;
some nakades can lead to seki, others don't ;
(e) kings in big dragon: case by case ;
if you have a non-alive dragon that's absolutely too big to give up,
you're all-in anyway, so might as well add kings ( except (a),(b), etc. ) ;

interesting to see new strategies and tactics...

Even for a seki shape, you want to play kings if you're 100% sure your opponent can never, for the rest of the game, use their seki stones as ko threats to kill your seki kings... Hmm.