Acrylic paints are not compatible with mineral spirits.
Model Master Acryl is "thin" enough out of the bottle to airbrush.
Tamiya needs to be thinned with an alcohol based thinner, like their own. Using straight Isopropyl works, but can cause "tip dry" as it dries very quickly and can clog the airbrush.
I spray Future straight, never thinned it before. I hear you can, and again use isopropyl alcohol.
I suggest getting cheap kits to practice on. Model Master Acryl or Tamiya Acrylics wash right off with Windex (the blue kind), and can be painting again and again.
Keep practising and don't get discouraged!