I like your plan. It's important to note these two things:

- The flush came runner-runner
- Villain check-called the flop

Which means, whatever his reasons for getting to the river, it was probably not to draw to flushes. Lots of his hh hands were check-folded as air on the flop.

I therefore think it makes good sense to bet small and target his weakest bluffcatchers (non-flushes). He should have many of those, and few low flushes. I might bet even smaller to exploit that (reads would be useful, too).

If he check-raises, life gets interesting, but you cross that bridge when you get to it. By doing a little range analysis, you should get a pretty good idea about how much value/air he gets to the river with, and the likelihood of him overbluffing. (With lots of air and few nut flushes in his river range, he could be c/r'ing the nut blocker far too often, without realizing it. And he should not bluff much else, because your range is not capped.)

i like to go a little bigger here on the river say 14, hes still going to call with all bluff catchers like zen said, all sets and big two pairs will call imo, bet 14 and probably fold to a check raise

I am in the bet bigger camp on the river.  I don't see a KQxx hand call often enough and really think that the bet size will have little effect on that that.  We should be able to get more value in the long run getting called by a lightly narrower range.  I probably bet more like 16-18 here assuming to get called by two pair or better.