i'd call the flop with stacks this deep. we have 6 nut outs, and will pick up a well-disguised FD on ~1/4 of turns. just don't convince yourself he's bluffing is he goes crazy on a spade later in the hand and i imagine we would have adequate implied odds to see one more. 3betting here sucks imo because i doubt he has very many pure bluffs. which leaves semi bluffs (spade draws) and perceived nut hands. that range crushes our five-high and is very unlikely to fold this early in the hand