[Tilt]

No, I like your bet size as is. A spade draw or unmade straight draw may still call (but may muck to a bigger bet). If you are called in one or two places, a smaller bet gives you more room on the river to maneuver.

If you are flat called in both places to a river blank you have enough behind to make a block/value bet on the river and fold if they come over the top. If your read is that one of them has a weak straight (based on your knowledge of the opponents) and can make a fold you can pot the river.

If you are called in both places to a double scare card (broadway spade) its an easy check/fold I believe.

If you are called in one place to a blank value/block the river or make a read above against a possible weak straight. If you are called in one place to a non-broadway spade, value/block bet, to another broadway card I probably just check/muck.

There is an argument for just potting the turn and folding to a raise. Its a pretty close decision. If they were tricky opponents they might smell the smaller bet as weakness and semi-bluff you off. I think for situatoins just like these its important to develop a history of betting less than the pot or even check/raising the nuts. If you only bet the pot with the goods until the river you can get read pretty well.