I've got this villain running at 22/9 over 1225 hands with a 4% 3bet. He multi tables and I would expect this guy to be tracking hands, he should see me as a 23/19, maybe slightly looser.

This guy loves the 3/4 pot button on Boss, he will use it for all 3 streets and I've only ever seen it done for value. He plays very straightforwardly and as a consequence he should've noticed me playing very straight forwardly when he has shown aggression.

On the river I think bet/call is out of the question, I'm not even sure if he raises all flushes! I do expect him to check behind Kx like always here so if we check, I think it's to check/fold . He tanked a little before calling turn if that makes any difference?

So it's a toss up between b/f and c/f in my eyes, what is your preference and what's your sizing if you bet? Note there is $120 effective on the river with the pot at $62.50.

BossMedia Game #1839516201: Table Table TH 2367 - $0.50/$1.00 - No Limit Hold'em - 22:37:15 - 2009/10/28
Seat 1: Hero ($148.59)
Seat 4: kenitra14 ($96.50)
Seat 3: MikeyWest ($251.25)
Seat 5: mabugly ($27.07)
kenitra14 posts the small blind of $0.50
mabugly posts the big blind of $1.00
MikeyWest is the button
*** HOLE CARDS ***
Dealt to Hero [ ]
Hero raises $3.00
MikeyWest calls $3.00
kenitra14 calls $3.00
mabugly folds
*** FLOP *** [ ]
kenitra14 checks
Hero bets $7.50
MikeyWest calls $7.50
kenitra14 folds
*** TURN *** [ ] []
Hero bets $18.75
MikeyWest calls $18.75
*** RIVER *** [ ] []
Hero ???

So how much are you betting?
His range is exclusively Kx/flush draw

I think its Kx way more often than flushdraws unless its like 87c.

The fact it's a definite fold to a raise make's me think its an even easier value bet since we don't fear a bluff raise at all.
Half pot seems good to get value from a KJ or something.