ok, first you have to prepare the surface, since is a plastic kind off, xbos right?,then what kind of job are you thinking,if it is going to be very detailed or not.the kind of airbrush is gravity fed, so you can reduce the paint up to 10 to 1 reducer-paint(even more),and go as low as 5psi.but this is only you doing a very detailed job.not tried createx and all of my jobs are on illustration surfaces,but the philosophy stands.so when i reduce is to start light and darken in the process,so to avoid mistakes and if done, correct them easily.
hope this helps!!!