RE: Finishing for a TF GS P-51D
Orange peel or fish eyes?
Orange peel is caused by the paint not leveling out so this might be just a set up issue with the paint consistency and temperatures.
I found that usually the cold weather gives me some orange peel but not often.
Make sure your paint temp is not cold, so above 70 deg., and try to paint in a warm place. This helps the paint flow and then flash off correctly.
The other issue is when you layed down the first base coat was it done smoothly or was it dusty and dry? If it was dusty then it can make a texture under the final coat. The base coat has to be smooth and flash off before the second normal coat is painted on.
Fish eyes is a condition when there is an incompatible chemical on the surface of the part like silicone or hand lotion or body oils. The paint will litterally leave the area and spread out looking like a bunch of fish eyes. This requires a good cleaning and degreasing of the part and repaint. If this is on top of the primer then its just a cleaning problem and more prep work.
So even though its expensive try to test and set up your paint gun and paint on a practice part or sheet and see how this paint behaves for you. Get to know it and it will go smooth from there.
Also when helping to dry the part do not apply direct head to the painted surface. Apply the heat indirectly to heat the part from back to front or inside out. This will let the gases escape from the painted side and not trapped by the paint itself which takes longer.