$109 tournament

Hero SB
Villain BB - unknown
40bb eff stack
Everyone folds to me.

Preflop: (pot: 2,6 BB) Hero has 9c 7c.
Hero opens to 2,5 BB
Villain calls

Flop: (pot: 6,1 BB) Ks 8d 2c
Hero bets 2,1BB
Villain calls

OTF i have easy cb.

Turn: (pot: 10,3 BB) Ks 8d 2c 3d
Hero bets 7,21BB

I chose to cb 35% OTF. It is quite a dry board, so this cb is big enough. He probably expects me to cb OTF a lot and my sizing is not very big, so i do expect him to have many floats here. Turn is basically a brick - he only improved with some diamond floats. So i think i have profitable second barrel OTT, XF seems to weak to me.
Sometimes i am little confused when i cb OTT with almost no equity. How do you usually decide in these spots if you should bluff or not? And which hands would be best bluff candidates in this hand?
Thx