I had used regular clear coat spray paint, whichever one I have on hand (Krylon, DupliColor, etc). All worked great. DupliColor dries the fastest.
Just spray 2-3 super light coats, to avoid puddling and runs. Let each one dry, as per instructions, then apply the next one.
The first time I had applied the vinyl's, I neglected this step, and had smudged some of the black paint on my Mercury wraps. Not a big deal, but definitely avoidable.
I am, personally, not a fan of baffles.
The better ones trap the plastic motor ejection cap and don't let it fall out.
The crappier ones singe the chute, and prevent you from accessing the FWD end of the motor mount if you need to push out the stuck engine with a dowel (especially common when friction fitting motors).
For my Interceptor E, I'm seriously considering installing 1010 rail buttons.
Either in addition to (aerodynamics are not much of a concern on this model), or instead of launch lugs.
a