Tempering the belly is a simple matter. Once the bow is roughed out and floor tillered, you clamp the bow belly-up onto a 2x4 into about 1 1/2"-3" of reflex, with 1 3/4" seeming to be the best, and take a heat gun to the belly. Go slow, and evenly. It should tunr a nice, even, dark brown. Marc St. Louis says that each limb should take about 20 minutes or so to properly temper.
You can also sinew back it if you have the sinew to do it. I made a nice 62" hickory, still slightly green, backed with sinew and pulling 60# or so at 27". It only took about 2" of set, and considering it was still green, I was impressed. It shot well.