Does the torch body size have an effect on the flame if the tip size is the same? I.e. if both your arm size torch and my little torch both have an equivalant Victor #1 tip on them, should the flame be about the same on both?

I can definitely see in Paul's video his torch angle is much shallower, his flame is more glancing across the tube, whereas I was pointing it more perpendicular, so that is a good observation, thanks.

However, Paul does hold his torch steady at the base of the boss for a solid 5-6 seconds when making the initial 'tack' without burning up his flux, so I think I'll whip up a similar heat sink and try again with his angle of attack. I still have a gut feeling that his torch has fewer BTU's coming out of it despite the larger tip size. This is counter-intuitive to me if his acetylene only flame is also soot-free after lighting.