As far as penetraing oils...NOTHING out there beats Kroil,i learned about it from working around Millwrights on jobs and they work with some of the worse case rusted and frozen bolts out there...
I used it on an old Chevy 327 given to me that was froze up for years,sprayed it in the cylinder and rods,bearings and crackshaft..came out the next day a little tug on the crank with a ratchet and it started turning over...i can honestly say this stuff saved that engine from the scrap...
I agree,if buiying a torch set,buy the torch set seperate and go buy the bigger bottles,you'll find alot more uses for it then just heating bolts up once you start using one.
If you are sure you are only going to use heat for loosening bolts only,then the mapp gas set will work..i have a set and comes in handy on little things at times.
Keep an eye on cragsllist for torch sets and bottles,,they pop up here and there at pretty good used prices.
Smith and Victor are to the 2 common well known torch sets and easily get different tips and parts for them anywhere,most others are copies of them..Victor is top notch with Smith not far behind.