The sizing seems fine. I do not think the sizing would determine if villain calls/folds on this board (i.e. villain will flat regardless with 10x / JJ / QQ / Ax). In addition, we can also double barrel with less risk with your current sizing.

CBet in this board is really good.
You could also bet 1/3 on this board.

being from sb and 3 betting vs co ( I assume not 3betting way too much) this board is quite good for us. We can attack it really well. Sizing is bit interesting here, our range have QQ,JJ,KK,Tx and they prefer small bet or check, and A9s,A5s,A4s.... which we can bet small or check as well.

3bet probably too loose, sizing is okay anything between like 30-70~%, but I would just use 1/3 and get him to make more mistakes, although we'll win a pot a bit less often, we will probably generate more ev

You have raw equity and nuts advantage so I think cbet 1/3 on this board is totally fine.

But I think the most important is how your opponent's range looks like.

For me, CO vs SB 3bet calling range is something like ATs ~ AJs, 88(99) ~ TT(JJ), KQs, KJs, AQo, some AKo, QQ, AA, KK. And I think you need to at least double barrel to take this pot if they call your flop cbet and the turn bet is expensive and you have no information about your opponent. It's a trade-off after all.

I'll sometimes X on this flop, and sometimes cbet 1/3x and cbet turn 1x.