What should I bet to protect a made straight from a flush draw?

[tree_stump]

He had odds to call if he was guaranteed a win if he hit... With 63, he made a mistake but got lucky.

IMO, you don't need to raise quite $22 for him to make a mistake, but something in the 15-16 range (which would force him to call $15 into a $31 pot - so he wins $46 for his $15, and 3-1 is not quite enough for his flush draw... In this game, he's calling just about every non-overbet, though.