hand 1 - 1/2 psb is my default c-bet sizing in 3b pots. Here I'd want to know his fold to c-bet before deciding on sizing - although sample size will be small. Turn is gross cos it's gonna really mess with your action from 88, thing is that it doesn't hit him hard either. I think his flop calling range could easily be sets/66+ by the way. Check-decide is ok, block-decide $10 is ok too but it sucks that he might fold JJ that way. Cool thing is that you'll often get a hero call from TT on the river if the turn checks through.

hand 2 - i really don't like calling 3-bets out of position without reads and especially if you would never do it with KK+. Thing is, a 19-15 over 20 could easily be a 12-10...

hand 3 - note that 3% 3bet from sb doesn't tell you anywhere near as much as his 3b/call/fold vs steal stats. I also hate the range you assign him pre-flop, if you think he isn't 3-betting some 78s type of hands then, i dunno, you're probably wrong. He's c-betting this flop all day with his entire range too. If you're calling AK vs the 3bet and want to fold when you get a near-perfect flop then you fucked up pre-flop. As played i'm trying to decide whether raise or call turn is better for value. I prefer calling the turn and calling/shoving any river.