I have covered them in plastic film and then painted the trim colors on. The only problem I had was the paint cracked over open areas about a year later. I used Aerospan film from Balsa USA and 21st century spray from Coverite. (The Aerospan is Solar Film from England)

Maybe someone knows of a paint that is flexible enough and will stick to the plastic?

I would fill the seams in the super coverite cloth with polyester spot putty made for automobile body work. Laquer based spot putty will shrink a tiny bit and may show through the paint over time. I filled the weave of the cloth with dope and talc in the past but I used auto body primer on my latest project. It's too new to know if it will work out over the long haul yet. The most likely problem would be cracking over the open areas of the structure.

Adrian