I have used one of those torches. They do work rather nicly. The tip is a two piece system that has a different seat than the rest.
I wouldn't buy one as, where do you purchase parts for it. Dependibility in the long run I wouldn't know. I only used it at a demo. Never on a job sight!!!

As for cutting sheetmetal with a torch. turn the heat down low. have the ox at 20 psi instead of 40 psi. point your torch at a 70' to the work. Try that. I know a plasma cutter works a whole lot better, If you dont have one use what you have.

ROBERT