A very straightforward question.

Table is a rare treat; it's full of passive old men, who like to see flops by limping. Post-flop they have no difficulty folding when they don’t hit. Hardly any aggression.

Hero opens KhJs to 20, two callers.

(65) Flop AsQdTs

BB checks, I bet 30, first villain folds, BB calls

(125) Turn 3d

BB checks, Hero…

What should our sizing be in a spot like this against a guy like this? We are 1200 effective.

When you flop the nuts on a wet board against fit-or-fold Vs, there is no need to protect your c-betting range by c-betting small. Either they have something like TP, a FD, or middle pair and a gutshot, and they'll happily pay 2/3 pot+, or they don't have anything except maybe bottom pair, and they're not calling even your small c-bet. The only thing you're keeping in with this small sizing is Qx where X is not a Broadway card, and that is a miniscule part of their range. C-bet bigger.

AP, it's very unlikely the 3d helped him. Guys like this don't call because "I have a BDFD to go with my bottom pair," so if he does now have a diamond draw, he also has TP. Meanwhile, the rest of his flop calling range is likely calling any reasonable bet, so make it large for fat value. I go $90+. But man I wish we had c-bet bigger this deep.

Preflop positions matter a lot on this texture. If we are playing pure exploit and one was in early position I would start potting or more. Two pair is going to pay 3 large bets, same for bottom set. Top pair isn’t folding flop.

On turn not much has changed. I’d bet 100, or more if I have image problems. We need to punish them when their range is strong for all the other times we have to barrel them off marginal hands.

I was in early MP, one caller from LP and one from the blinds. No limpers. I felt I could safely open this hand at this table. I would fold in tougher line-ups.

Hero bets $65-$85.

I would bet this flop when I hit it pretty hard and otherwise checking. It's also exactly the kind of flop that smashes weak players' calling ranges i.e. Ax / unsuited broadways / suited rags. Lastly we're multiway. So all in all I go $45 on this flop and I could accept even more.

Turn I'm probably going $85.

If he calls my plan on the river is to make it something like $250 on a brick. If the front door flush comes in I guess I go $125 / fold.

^
This is my thinking as well, though on a brick river I'd lean towards an over bet.

Overbet will lose fat value on this table.

big, BIG, BIGGGGGGGGGGG

if they are passive (and I have seen this so many times) they don't 3b AQ AK TT or even sometimes QQ.. are you trying to milk A6s which is probably gonna fold on turn anyway?
So bet big flop, bet big turn and bet big on river to target the strongest hands..

Result: I bet 100 and he quickly folded. He probably had nothing much anyway, like a gutshot or middle pair type hand.

very strong hands (where you even don't other strong hands) I'd just go for it and like Brunson said, hope they have something good as well

Turn I would go 90, about 75% pot. Amount you went was good too.

Generally I'm not looking to overbet a spot where either of you can have flopped the nut straight on the flop amd the nuts haven't changed. This way we keep in AJ, maybe even weaker Ax that are just praying you're on a flush draw.