For heat in between propane and oxygen acetylene I like a plumber's "air acetylene" torch with a B sized tank. I originally bought two sets new and now pick them up at flea markets and junk shops for less cost than the gas in the tank.. I keep saying I don't need any more and then can't pass up another tank or setup dirt cheap. I initially had 2 tanks filled but that was 12 or 14 years ago, they last a long time. Several I have are Prestolite but my favorite is an all brass/bronze nickle plated Smiths torch. Just need to find a variety of tip sizes for it, or order them new.
For more portable try an MC size tank, same torch kit.
