Kevin...You got it right. You win a cookie! LOL
To expound, more of the story is as follows:
The PPG "Deltron" basecoat/clearcoat system we are referring to is called "DBU". It uses DRR 1185 Reactive Reducer, which as Kevin Greene has stated, contains a catalyst which promotes the hardening process, and reduces the viscosity of the material. There are other numbers for the Reactive Reducer that are suitable for various shop temperatures. I use DRR 1185 here in San Diego, as it never gets very cold or hot here. They make a hot temperature reducer, (think of Phoenix) and one for colder climates like Kaslispell, Montana.
One of the things to remember, is to make sure that you get the clearcoat applied within about 24 hours of the basecoat application in order to get the best adhesion. If you can't do that, sand the surface lightly and re-spray the basecoat before proceeding with the clear. You don't need to sand enough to remove the first coat...just scuff, then re-shoot.
The basecoat will dry to tape in about 20 minutes. I feel that it is wise to allow about 45 minutes before taping for the next color. If you work fast, you could possibly paint three or four colors in one long, hard day. Apply the graphics from Pro-Mark, Blast on the clearcoat, and you have a fuel proof, ultra glossy paint job!
A good clear coat is PPG 2021 or 2042 high solids clear. PPG can offer you guidance on compatible clears. Some clears are NOT COMPATIBLE.

The name "Deltron" is confusing to some. It is used in the original two part formula (DAU) acrylic urethane enamel, and then came "Deltron 2000" which is another two? part, then Deltron DBU, the subject basecoat/clearcoat form of "Deltron".
Then along came PPG "Concept", which is a premium gloss two part acrylic urethane enamel. That was in response to EPA rules that regulate the amount of VOC's (Volatile organic compounds) in paint formulations. The EPA is doing a great job of keeping me confused.
When you go to the PPG store, pick up some of the free literature on the various products. They are quite educational, and easy reading. Ask for a Full Line Catalog. It will solve the incompatability questions you might have. I'm sure that the PPG store people can answer any questions you may have.
Other paint companies make comparable products, so I'm not just blowin' the horn for PPG. I just haven't used anything else, as they are close at hand and have been very helpful.
A good spray gun/compressor setup is invaluable. Good equipment and good technique makes the difference between a good paint job and a great paintj job!
You should ask Bill Brundle....He's a great painter!

Good luck!

Harley Condra
BVM REP
Team JetCat