crap.. I meant to copy and paste out of this comment but deleted it instead.

Proper hand example with JdTd is below. My basic point was that it's impossible to say what size is best on the river for a thin value bet and that it entirely depends on villain, board and image.

If my image is bad I am more likely to bet bigger when draws miss.

If villain is stubborn or spewy aggro, I'm more likely to bet very small with a mid pair type hand and hope he stubborn calls worse or c/r bluffs over inducing small size.