How close can I hold a heat gun to a vinyl window to soften it up, without...

[Michael_Samuels]

...damaging the vinyl? Need to stretch (un-shrink a vinyl convertible rear window)… I need to regain a couple inches over 3 ½ horizontal feet, and preferably an inch vertically over 2 vertical feet

 

[ShaneL]

Try to stay about 3 to 6 inches away from the window and you should be fine.