Tamiya Acrylic thinner mixed with GSI paints

Luis - I haven't used those paints but if they are water based, Tamiya thinner might cause them to "curdle" like sour milk almost.. I use Vallejo acrylics which are water based and supposed to be thinned with water.  Someone else asked a similar question so I tried it and needless to say I was greeted with a mess when they mixed.. or didn't mix as the case was...

Being that the hobby shop guy mentioned thinning them with water those might be water based as well..  you could always try a little spot and see what happens...

I've tried it. It doesn't work! The paint comes on too thick. Come to think of it, I've never been able to thin GSI acrylics successfully, ever!

I will never use GSI acrylics ever again.

If you really need to, I guess you can use GSI's Mr Color Thinner, but it's really for lacquers.

Good luck!