@realjohnboy,
I only use acrylics for wood carvings , I dont like it for painting just because it does dry so fast. Ive used Jo Sanja and Kamiya(?) sp.(?) because these have really brilliant colors for cartoony style carvings.
I always thinned them with isopropyl alcohol (its so cheap at 70% strength and its less flammable.
I used to thin the Jo Sanja down to a thinner mix that would be good in an air brush. even then I wouldnt leave any pigment in the receptacles or the spray bottles. It was always easier to mix a quart bottle mess of piment and then just dip it in the spray receptacles as I needed it.