Anything less than $3.50 on the flop is small imo... There is just no reason you shouldn't raise large here. His min-donk lead weights his range so much towards draws, pair + draws, that we know this villain is going to continue with that we should be raising large with all of our value hands to emphasize his inevitable calling mistake.

As far as the turn, as stated you are getting insanely good odds to call. But also, villain is getting insanely good odds to draw if he is behind. It's too late for me to go plugging in ranges or anything, but we have such great equity when behind, and his range is still probably weighted towards non-nut hands, that raising and getting the money in can't be a bad thing.