Here is a link to a PDF on brush-painting machinery - Of ALL kinds.
The info in here is absolutely spot on - I've followed this and gotten brush paint jobs that flowed out perfectly, looking like they were glazed or something -
I really recommend it.
Also, check out some web articles on using the "Majik" hardener from Tractor Supply with Rustoleum paint :
High Quality Brush Painting - VintageMachinery.org Knowledge Base (Wiki)