So if you're planning on covering spot with a sticker anyway.... Why not try a light coat of nail polish clear hard coat first. (I understand) it is normally used over the nail polish.

I generally use fingernail polish to color-match nicks or chips in the paint. But the polish will wash/wear off in time if not hard-coated. So I use the clear hard-coat. Then I wait a couple days and use car polish and wax to smooth-out the finish. You might want to try the same process... minus the nail polish (as your paint remains intact).