RE: Sealing surface gaps
opjose - I am positive about removing the bottom film. I have covered planes before and I know what to do. In this case, considering the Ultracote was transparent and to be absolutely sure (although obvious) I even tried to stick the backing film in case that was the real film and nothing!
I'll pick up some Blenderm at a pharmacy to check it out, sounds like an easy way to do this!