Thanks for the follow-up.
The iron at 325 is doing a good job of lifting the wrinkles ... they swell up a bit, then settle down ... after which I can go back over the finish with firm pressure and bond the film to the wood.
I tried one patch with the heat gun, and the risk of damage (from my clumsy effort)became apparent quickly.
I'll give the clear coat a try ... usually I seal Monokote edges with clear (laquer) nailpolish. I also go over the entire plane with Meguiar's 'Deep Crystal' automotive polish, which not only gives a fanastic sheen to the plastic film, but affords some protection from exhaust residue.
Cheers!

PJ