Doesn't exactly answer your question, but I will give you something to consider or try to work into your play. It might help.
First off, if you are SB then you act first postflop. So you are check calling every street. I'm not trying to be mean, but in my scenario this is an important detail.
So if you flop something with middling equity (TPWK, middle or bottom pair, flush draw, open ender) and it's not a flop that crushes your opponents range. Your opponent is making reasonable 1/2 pot plus bets. I use checkraises quite a bit here- bump it 1.5 what the opponent bet (if he bets 500, bump it to 1250 which is 750 more than he bet or 1.5*500). Sometimes they'll fold out and you get a nice little boost to your stack, sometimes they'll reraise you making it an easy fold but still cheaper than calling down 3 streets, other times your flop c/r will slow them down, get them to check back the turn, and give you the opportunity to realize all your equity by making it to the river, let you bluff the river, or fold to his bet when he leads.
It's way cheaper to put in one standard c/r than it is to call down every street. Hope this makes sense, I'm kinda tired right now.