I can't speak for pollyscale or medelflex but I do use model master (by default since no hobby shops in the area carry anything else) Their airbrush thinner works great with their paint but I found that some other thinners will cause the paint to coagulate. Stick with the recommended thinner for brushing, clean-up with whatever is cheap.
Also, would still at least try to work with thinned paint. The Eclipse can spray lines that are unbelievably thin. I've gotten model master lines smaller than 1/16th inch. I used to think people were lying when they talked about lines that thin from an airbrush.