If you lead out on flop, you won't get action unless they are holding 44-JJ. Really you don't make anymore money by leading out with a continuation bet on flop than checkraising the turn. With a rainbow flop, i don't mind a checking on flop at all. Unless I KNEW he held something like TT, I may bet, bet, bet, or check, bet, bet. I don't mind the check on the turn either. With the board showing 5-4-Q-8, I think your check will be followed by a bet by one of your opponents maybe 4/5 of the time since your hand could've easily missed this board. If I were one of your opponents, I'd find it almost irresistable to not bet if I was checked to twice, regardless of my holding.

Reasonable hands Dubble could be betting on turn are 55, 44, 88, AQ, KQ, QJ, A8, JJ down to 66 excluding sets, flush draw + gutshot draw, flush draw, any two cards (bluff). The action on flop suggests that neither of your opponents have any hands containing the case Q or any of the hands that would've made a pair on the flop. I think he bets 66+ on flop. Hands that didn't bet the flop are 55, 44, A8, flush draw + gutshot (like A6 spades), flush draw, and any two cards. Of these, the only hands you may not want to raise are A8 and any two cards.

Since you have no reads, you won't make much more money if he's bluffing (unless he's a known big bluffer), you won't make any more money against the flush draw unless he makes that flush and you fill or pairs up, and you/he bets for value. Only hand you probably don't want to raise to 800 is A8, but he may call your raise with A8 anyways thinking you're bluffing (not likely given you'll have invested 2/3 of your chips into this pot). I think your raise to 800 was correct. A raise to 800 gives him 1700/500 or about 3.5 to 1 pot odds. When he's on a flush draw or flush draw + gutshot he'll be a about a 5 to 1 dog to catch one of his 7 outs (2 of the remaining 9 spades give you a boat) or about 4 to 1 dog to catch one of his 10 outs. Lastly, if he's holding 55 or 44 and slowplayed the flop, you'll double up if you raise on the turn. But if you smoothcall and a spade, 6, or 7 comes, the action could get killed.

Additionally, if you think he might be too scared to bet 66+ on flop, there's a decent chance he'll call your checkraise on turn with something like 66 or TT. If the board showed 5-4-Q-8, would you call a checkraise to 800?

Basically, you would raise any draw and raise any made hand. I'd say your raise here was the optimal play. And, a raise to something like 900 or 1000 is arguably better.

-mike