This hand comes from a $250 6-max from the NJ pokerstars COOP series.
Villian: 23 vpip/23 rfi/8 3b (3k hands)
Villian is arguably the best reg on the site.

PokerStars - 125/250 Ante 30 NL (6 max) - Holdem - 6 players
Hand converted by PokerTracker 4

BTN: 117.29 BB
SB: 86.27 BB
BB: 85.06 BB
UTG: 85.73 BB
Hero (MP): 140.27 BB
CO: 94.42 BB

6 players post ante of 0.12 BB, SB posts SB 0.5 BB, BB posts BB 1 BB

Pre Flop: (pot: 2.22 BB) Hero has Q A

fold, Hero raises to 2.5 BB, fold, BTN raises to 8 BB, fold, fold, Hero raises to 20 BB, BTN calls 12 BB

Flop: (42.22 BB, 2 players) 4 3 7
Hero bets 12 BB, BTN calls 12 BB

Turn: (66.22 BB, 2 players) 5
Hero bets 108.15 BB and is all-in, fold

Hero wins 66.22 BB

I decided to 4-bet this pre because this was a 6-max and my opens were facing a lot of 3-bet's from the entire table.

As for the postflop betting, I'm trying to rep QQ+ here, hoping to get him to fold 99-JJ and AK on this turn here.

Any comments on the preflop 4-bet and postflop bets?

I was debating between betting flop and x/r, but ultimately went with bet because villian leans toward checking back IP when OOP was preflop aggressor.

Edit: I also think there's some merit for sizing up higher on the flop so the turn shove in pot sized, however, 1/3 sized bets are my standard size when I'm the preflop aggressor in 3bet+ spots.

Are you ever doing that with AA?

Not 100% of the time, but yes.

I do not like 4!/fold with AQ with this stack depth. It makes sense emotionally that you have a hand, but I would keep it mostly to hands to gii with and bluffs. There are some advantages in that AK/QQ+ are usually 5-betting and you will not get stacked by them. However, we the aggressive dynamic, it is possible you could get 5! light.

The shove is actually for about 1.25xpot. You were probably ahead since he folded. You are not representing AA at all, but 88-QQ. It looks like AK though, since he shouldn't expect you to usually 4! AQ. Because of the wet board, you can sort of represent shoving for protection. You have 3 or 6 outs against a pair, and you might sometimes be called AhQh, AhJh, Ah2h, or xh9h. I do not like it, but I would be interested if anyone has a better play or plan.

Hero picked up a gutter on the turn, so we often have 10 outs here when called.

One thing OP mentioned was defaulting to 1/3 pot in tight range spots; I think that is good, but you do want to try to balance your bet sizes so that your turn shove is a little smaller. There is nothing magical about 1.01 pot vs .99 pot, or even 1.1 pot vs 0.9 pot. It doesn't take a much bigger sizing on the flop to get your turn jam closer to 1.0.

I do think you get better leverage with your flop bet when your turn shove will be for close to pot, especially if you use a size that isn't a click of a predetermined to fraction of the pot. Villain sees you bet say 18BB, he knows pot is behind, and likely coming on the turn.

A lot of above is psychology as well.

What factors are you using to determine your flop bet size here?

The most important thing is what factors were you using to determine flop bet sizes?

If you were typically always betting 1/3 pot then that would be the amount to choose. If you were more GTO and betting 1/3 when the flop favored the caller and 50% to 66% when the flop favors the raiser then this is an interesting flop. I think it favors us more than the BTN because we have a lot of QQ+ here and not as much AK. And this should miss BTN's range as well except for 77 (though his PP's benefit just not as the nuts).

I also agree with 3for3 here. If we are going to jam the turn on virtually any card then I would make the flop bet a little more so it is closer to a pot size bet. Effective stack size on the flop is 97 bb's so a bet of 18 bb's would leave a pot size shove on the river. Personally I would use the same bet size as pre-flop at 20 bb's.

The best way to do that would be to have a larger 4-bet pre-flop. By raising 2.5x you will likely not get a fold from somebody in position. I would make it more like 28 bb's pre-flop. Then on the flop we can make it ~19 bbs so the pot would be 96 bb's and the effective stack size would be 72 bb's. Making the turn shove look like a strong value bet.

Yeh, both posters are right: preflop sizing is fine but could be bigger. Also, you can go bigger on the flop. You could even half pot the flop and shove the turn for about 90% pot.

Incidently, this is a close to ideal board to shove the turn with AQ/AK. You could play slower if you hit and there are some flops you might cbet / give up or x/f on.

The turn card gives you more reason to shove, as it create a wet low board that it is likely neither player hit hard.There are draws to protect against if you had a pp. As implied, you have 10 outs against TT (which should never fold to the push). You are also shoving partly to protect your hand when ahead and to prevent being bluffed off the best hand.