Thanks for the tips. I have been experimenting with Liquitex Glazing Medium in a roughly 3:1 ratio with Reaper Naga Green and Fireball Orange. I like the results (will posts photos when I get it a little more finished). The effect does seem similar to the Reaper Clear paints, though slightly more opaque. I will experiment more with the ratio and a few more colors.
I enjoyed the class in RVE on creating a starfield cape with Clear Blue/Magenta/Purple. I would like to experiment with star fields of other colors but am having a hard time getting the paints thin enough to be like the clear colors. Does anyone have recommendations on how to make other colors appear to go on like clears?