Covered a complete fiberglass fuselage with Monokote back in the day.
Unpainted
Must be polyester not epoxy
Iron on high heat
Start in middle and iron in a circular pattern working your way to the edges.
Pull the snot out of the covering while iron, use stretch rather than shrink.
When my old friend ask me to cover his fuselage with Monokote, I laughed and said it would never work, then he took me to a booth at Toledo where they had several covered with Monokote, pretty sure the company was from Ohio, maybe AHS or something like that. They had a whole line of glass fuselage/foam wing airplanes, his was 1/4 scale Laser. Had to be before 1994.