the stuff is absoultely fool proof, this one was a test, as i wanted the one on my silver bottom to be blue. i sprayed heavily from an inch away and as soon as i saw drips i stopped and it all evened out very well despite my poor way of painting it. id say 5inches is the best spot when painting.
you need an exacto to cut the layer of rubber so when you take the tape off it doesnt rip off all of the paint on the mask, it becomes very rubbery and all of it becomes a stretchy latex-like area, the exacto cuts through this easily and leaves a clean look. pics or shens to whoever said they used it on thier mask first