against a competent villain i would prefer checking back the turn, but the more offsuite queens with a spade you think he defends pre, and the more pockets with a spade he calls, the better the turn bet gets. if you decide to bet, i would certainly bet bigger though.

looks nice played, can check turn and bet bigger river. Think villian will have quite many PP here, which he calls at least one street, and other part of his range sets +. So I don't think we can bet river after turn if we don't know that he is weak player and his range wider(and he calls more)

Try to think about what size your range wants to bet in different spots rather than what your specific hand wants to bet. If you had bet a more normal amount on the turn, I'd have said that it was a somewhat easy fold. When you pick a small size like this I definitely think that it's possible that you've induced a bluff and turned your hand somewhat face up. Would you have bet that amount with QQ or the nut flush?