With a .5 mm tip you may have problems shooting a craft paint that is not formulated for airbrushes. A .35 mm tip will surely have problems. Craft paint pigments usually don’t shoot reliably because they aren’t ground small enough and they have no flow enhancers, so they tend to clog your tip. That said, sometimes you luck out and your batch happened to be ground small enough. It’s a crap shoot. But most of us eventually learn to go with only airbrush paint to avoid the aggravation. Just about anything can be used to thin acrylic paint. A mix of water, alcohol, and a few drops of glycerin is one that works. Ammonia will eventually eat the chrome off your airbrush. Yes, Pledge clear acrylic floor polish also works but it dries to a very hard coating that is hard to remove from an airbrush if you let it dry and accumulate anywhere inside. I tried some and had to extract the needle from the packing nut with pliers after it dried. So I can’t recommend it.