10/20 PLO with optional $40 straddle. 9 handed. No straddle this hand and I'm under the gun+2 with 78910 with 910. I raise to $100 and get 3 callers :Button and both blinds. I have effective stack of $2,300 before the hand(all villains cover). Hero has typically been crushing this game but today stuck a couple thousand prior to this hand so image is probably a bit tilty

Flop is 389 SB bets out $400, BB folds, it's on me with the button still to act after me. I have top 2, open ended, with a back door flush draw. Villain is an older guy, normally plays tight but I've seen him make some head scratching bets and calls with less than the nuts. He got it in earlier for heaps with AA on a 579 board with 2 to a suit on the board and ended up chopping against two pair when they ran it twice. Would you raise, call or fold here? My read at the time was his most likely holdings were 33 or 1 pair or 2 pair with a straight draw(probably higher than mine). Definitely didn't think he had just an overpair as he did in earlier described hand, but couldn't totally rule it out.

I elected to make it $1,600, button folds and SB just calls. Turn is 5. SB puts the rest all in. I call.

Question is on flop, what is the best play?

standard raise with those stacks, wp

I probably raise the flop, too, but it depends a little on how BTN plays and/or what I expect from him or the vibe I get.

As played, calling it off is fine/standard.

Easy raise on flop. Easy GII on turn. Pretty standard hand on every street.