Chico,
The Ultra 7000 line is a paint system. There are primers, base coats and clear coats in the system. All of them use their own set of additives to make them spray easier, flow and lay down depending on the conditions they are sprayed in. The RHF65, 75, etc. are stabilizers that you add to regulate flash time depending on what temperature you are spraying at. The BCS line of stabilizers have characteristics that also help when using metal flake, etc.
They do serve as a thinner to a point, but you may need to thin the paint more to make it perform with your equipment. The hardener is usually only used in the clear coat.
Check out this link, these "how to" may help.
http://www.sherwin-automotive.com/reference/bdp-ultra.cfm
