sorry if I am a bit confused but having built a Top Flight spitfire what are you painting with that product, the link is for thinner not paint and Pactra paint is not fuel proof unless clear coated, and really its recomended for lexan car bodies.

is your plane covered in plastic film or glassed?, using fiberglass cloth, and a resin, either water based polyurathane or a epoxy based material like Z-poxy is the typical glassing method before painting.
if its covered in plastic film then cut the camo scheme out of the film and clear coat it with lustre-coat for a dulled down finish.

a more apropriate material would be a fuel proof paint like www.warbirdcolors.com paints if you wanted to paint your plane, here is the link to the RAF color palette http://www.warbirdcolors.com/raf_home.asp its water based and has authentic colors for the era.

your also going to need alot more than 1oz of material to paint that plane, I used about 1 1/2 spray cans of auto primer to cover mine,so your looking at 2-3oz per coat of base colors for coverage.