[chh]

Actually, I decided to make a big bet here for the following reasons:

in general, a small bet looks a lot like i'm milking, a big bet looks more like I might have been bluffing or semi-bluffing on the turn and am trying to follow up now on the river.

So I was pretty sure a bet of 400 will be called at least 0.5 times as much as a bet of 150-200, probably significantly more.

I dont think he will check-raise as a bluff here virtually ever, but if he did, I actually think that perversely he would be more likely to do it against a big bet (thinking it is a follow-up bluff) than against a small bet (=value bet)

I like your point about "showing rags", however I'm just convinced that I would give up significant value against this player with a smaller bet.