You need to pick up Bob Downies airbrushing book and Donn Yosts DVD. Go thru both of them and you will become a much better painter.
no matter who you like you must get a smooth base first. Custom or OOB you still gotta be smooth. primer or not...you have to find a system that will
work for you. Lacquer , enamel, or acryllic....find what you like to work with all have advantages and disadvantages.
Good luck !