I can't answer your question, but I do have an idea for ya.
Have you thought about getting it powder coated? Think about it...baked on, hard glossy finish that's tougher than paint. Looks great! Unlimited color options. Not very expensive.
I just priced having my 30' trailer powder coated and I was really surprised at the price I was given. I agreed to remove all hardware. (leave the axles on, he said no problem there) I also agreed to have it sandblasted when I delivered it to him. The sandblasting wouldn't cost me more than $100. The powder coating was quoted over the phone at around $350.
Think about it...ya never know?
Buck