I have been using "Plaid Enterprises" brand Mod Podge, Matte finish. Whether there is a better brand, or the Gloss finish would work better, I haven't a clue! You guys tell me.
I was put onto this stuff by Andy Borgogna.
Where he heard of it, I don't know, as a search of Stunt Hangar doesn't show up anything before my posts. I am flying with Andy this morning, so I'll ask him. (later: He says a scale model builder friend told him about it.)
Currently, I am working on a full size Ringmaster and doing 3 coats of 30% thinned Mod Podge with sanding between. The sanding kills off the raised fuzz that a water based paint causes and any lumps and bumps from uneven brushing. I bonded Carbon Veil to the fuselage with the stuff and that worked quite well. When I doped over the fiber, a spot or two came loose, but could be rubbed back down with finger pressure. Final result was just fine. I plan to iron down light weight Polyspan, then Microlite park flyer film over it. Not as light as Coverlite alone, but WAY tougher and glossy. Overall, I hope for about a 15 point finish.