cash game 6-max
CO open 3bb, SB 3bet 12bb, CO calls.
hero: Ac 3c
FLOP 7c 4c 3d

I think this flop is better for CO range. So, I'm start with check OTF.

CO bets 1/3 and I call.

TURN Jh

check - check

RIVER X

My question is related to the possibility of a bluff OTR (with a big size like pot or 150%pot).
What kind of runout is better for our range ?

Obviously, I refer to a card doesn't complete flushdraw or improve our pair.