Whatever you do.. Make sure the prep is done correctly even if it means running around in primer til you can sort out a topcoat.
Painting no big deal but prep is everything especially on a grp car.
Having said that, some of the best, cheapest, smoothest, glossiest paintjobs I have seen have been brushed on and primered and undercoated with a mini roller.
Don't knock it, but check with some of the old classic forums.
I particularly remember a '30's Wolseley at a show once who's black paint was so deep and glossy like black glass. I was blown away when the owner told me it was brushed and took 3 months to complete and £90 and not an imperfection or run in sight!
Google Craftmaster paints if you want to know more..
View attachment 5811View attachment 5812