Well being this is your first post and I know nothing about you or what airbrush you are using ,
It is really hard to answer your question , Except by asking you more questions.
What airbrush? Nozzle size ?
what are you painting on ? T-shirts , canvas or something else?
what air pressure are you trying to use?
See we do not have crystal balls to see what all the new folks are using so you have to supply more information which by the way could have been done in a nice introduction thread telling us about yourself and what equipment you have so far.
Hi Chromatic, welcome aboard. Pop over to the intro section and tell us a bit about yourself. Also it would help us advise you if you could tell us what gun you have, and what you are painting on, and what you are hoping to achieve as the answers will be different depending on this. Createx I believe is for use on textiles and if you have a suction fed gun you will use a much higher pressure for example which may mean you won't need to reduce.
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.
If possible and in your budget switch to Wicked (by Createx) it is designed for all surfaces and is colorfast.
Auto Air Candies are pigmented candies which means the more layers of different colors it will Muddy up.
As far as reduction start with 1 drop paint to 3 drops reducer. AutoAir will reduce differently than standard Createx , But that is a good starting point.
You also may want to invest in an adhesion promoter so the paint bonds with the plastic controllers better.
But I strongly recommend you check out Airbrush Tutor - YouTube
Createx is prob the worst paint for beginners as you really need to get the reduction spot on to have any real success, especially at fine art pressures, tshirts and such ya can just blast away so reduction needs arn't as critical, its a case of experimenting with any paint you use..try mixing up 1:1, 1:2, 1:3 so on and so on, try these ratios at various pressures and see what works best for your setup and more importantly write it down..Not all colors will require the same ratios or pressures so experimenting is the key...GL