what kinda flop u looking for??? 666? I think you take the gamble and try and triple up here. Plus the 4 of spades can always come. In addition, if you think about it who is going to overbet the pot enormously with the nut flush? He is trying to kill a flush draw such as the ace of spades. I put him on AK or AQ, something that doesn't want to see a fourth spade which is perfect for you because your gonna be a huge favorite. In harrington he has an example like this except instead of having the flush he has the straight w/ no draw to a flush. I think this is a good chance for you to triple up.