Xman, I wish I could give you a better reply, but the fact of the matter is - I don't know.

I set the iron in the 180 -200 area, and then I will slightly raise or lower the temp according to what I need for whatever specific operation I'm doing.

As far as the heat gun goes, the gun I use has no "Heat setting", there is an air regulator in the back of the gun which I have in it's most closed position. This still gives me a little less heat than I would like, but it also probably keep me from burning holes in the covering