I want to spray one coat of clear over 4 coats of older clear that has been there for a year now , then cut and polish. When sanding the new layer of clear the if I sand down into the old clear, will it all buff out ok, or will that spot show. Since there are already 4 coats of clear there already and I will reclear the whole panel, I am concerned about getting a thickness buildup. This is to fix some nicks that occured right down to the base during the last year.