I appreciate you posting this, James, but I've come to find out that the local Nason jobber closed doors due to Covid and the Cincinnati store (50 miles) only keeps bankers hours and really only wants to do deliveries to local shops, no walk-ins!
I even called Nason and they referred me to their "local" dealer which was O-Reilly Auto Parts. When I went there they laughed and said they could order a gallon of white, black or primer and that's it. No mixing.
I defaulted to the Quanta shock paint which i think is a re-packaged Seymore spray-bomb stuff.
Thanks, though. Hope it helps others.