Hey Greg-- thanks for your thoughts and instruction. I would encourage people to follow it, and I will try to as well. Unfortunately, it is how I am wired, I like to experiment.
This paint/thinner thing is a mystery because from what I am seeing, it is contrary to the sound advice that Greg is providing. I like to push the envelope, not advising others to follow my jump off a cliff. Not you Gamera Cliff. LOL.
I just took a break from my work, and I ran a quick experiment. What I tried is with using the Model AIR, not their other offerings. So, I can't speak to how those will react.
Using mixing cups, I ran three tests.
1. Model Air paint thinned with Vellejo thinner.
2. Model Air paint mixed with Tamiya X20A acrylic thinner.
3. Model Air paint mixed with Tamiya X20A acrylic thinner and one drop of Vellejo thinner.
Of the three, I liked #1 the least. Pigment flow was spotty at times. Also, there were bubbles in the mix that seemed to cause surface tension in the paint, and the bubbles were hard to eliminate. Is this a problem in the real world? Doubtful.
The second option worked very well. There was no evidence of gelling and the thinner seemed to do a really nice job cutting the paint. Pigment coverage was consistent and paint flow from the side of the cup was very smooth.
The last option was in my opinion, the best. It incorporated the benefits of #2 with the added benefit of #1. This mixture was silky smooth, and the paint flowed even more beautifully.
The experimenter that I am, I just have to try number 3 through the AB. Worst case I will need to do a deep cleaning if it gums up. I will report back for those interested.