Steam, steam, steam! I lost count of how many good bows I wrecked trying to recurve the tips with dry heat. (I can envision belly fibers tearing apart even now.)
Dry heat is great for adding gentle reflex, general stave straightnening, and alignment. It's quick and there's no waiting around a couple of weeks for the wood to dry. Severe bends, though, need steam. Yeah it takes longer and you go mad waiting for it to dry, but not quite as mad as having worked hard on a bow only to have taken a shortcut and ruined it. You'd think I'd learn, but that's one mistake I still repeat from time to time. Steam it and you won't be sorry in the long run.