Finish on GRP?
 

Getting towards the end of my first kit build (very rewarding) and have decided on a gloss black based colour scheme, plus some colourful trim. Most of the plane will be finished in shrink film, but what about the GRP moulded cowl and undercarriage that are currently white? Clearly the cowl is a complex shape and the undercarriage will bend a lot. Is a spray-on paint finish a better idea for these GRP parts? Will paint be a problem (cracking) on the undercarriage due to flexing? What type of surface preparation does GRP require before painting?
Note: The GRP undercarriage has a smooth finish on the outer face, but is a fairly rough finish on the inner face.

Bewilderedly yours,
Bob (the builder)