I use both scalecoat and Floquil paint. I am using a lot more scalecoat than Floquil. On some recent projects, I used Floquil with a top coat of Crystal coat. When I tried to put on decals, I had a very hard time to position the decals. When I used scalecoat with no top coat, I could move the decals in place with no problem.
I have an old Binks Model B air brush which I have had for over 40 years. I have tried water based paints and have not had much luck, probably just used to the solvent based paint. For trucks (highway trucks), I have been using automative paint. It cost about half of what model paint costs, even when I buy 1 pint at a time. It also dries fast. For one project, I was able to match the color of the decal with automative paint. Roy J Meissner