I've recently thinned similar paints and airbrushed them. If youre going to do this I'd invest in a big pack of disposable paint strainers.
Thin your paints with water, 91% alcohol or windex (the blue color doesn't stay in it). Definitely add whatever substance you mix with a tiny bit at a time. Once you get it too a nice consitency dump it through the strainer to get all the gunky bits out. You may have to do this part more than once.
After that, you should be good to go.
Edit, I'd also suggest grabbing a spray primer if you can to promote better adhesion with the paint.