Depends on how you were taught. I've never had good luck at preventing oil canning with the heat and quench method. That's what the hammer and dolly work afterward is for. The guy that taught me really did not put too much heat in the panel. I even saw him park a car in the Texas summer sun and use dry ice to pop the dents with no torches involved. He always worked the metal with a hammer and dolly after the dent was popped out to prevent the oil can effect. I followed his lead and it has worked pretty good so far. I do use a torch for a gentle fast heat prior to quenching. Also depends on the dent itself. You just have to read the situation and use the right method for it.