A custom painter (North Valley Trains) who uses Tru-Color Paint exclusively for his projects has painted by hand AND Air brushed 2 locomotive shells. You can see his work on his website. One is a Norfolk Southern engine (air brushed), the other is a steam engine (hand painted).
Just follow the recommendation from various vendors and cure the FUD or FXD part in sunlight or UV lamp for an hour or so. Make sure the surface is clean (as with any plastic part) and you will have NO problems using Tru-Color Paint.
Trust this helps.
Martin Cohen, PhD