I don't know if anyone here still uses oxy-fuel torches for bodywork repair but i filled in a few holes in my floorpan with some decent results. I will post some before and after pics once I am finished.

Anyone have any good tips and techniques?

patience ... i really like to do this on a ground up restauration. it takes time and patience, but IMHO, it is lightyears better than bodyfiller bondo crap-o-la ...
Andy

i've done it to fill for pin holes and stress cracks. werx good. fill a little high and file down.

For small holes (pinhole really) it works, great and is world class repair...use right temp...don't distort metal with the heat... use moist bastos (sp?) for heat sink...yada

watch how much heat you put into a panel its easy to get to much and warp a panel.