Experienced vs rookies
In my books, I always recommend to stay with one paint system throughout any particular project, whether it is PPG, Dupont, or whatever. This is simply meant to avoid any incompatibility issues. There are all sorts of "stuff happens" issues that can wreak havoc with a paint job, that you don't need to test fate any more than necessary.
Can you get acceptable results by mixing and matching components from various systems? Probably, but do you want to take that chance? I sure don't want to sand it all off again if it doesn't turn out right. If you are an experienced painter, you can probably figure out how to correct most problems, but a rookie probably would not be able to save a botched paint job.
Just my two cents worth. By the way, How to Paint Your Car, 2nd Edition should be out next spring from MBI.
Dennis W. Parks
Author of Automotive how-to books