The good ones like Dan Smith's are made with minerals, so they do tend to
sink. If you get cheaper quality that is synthetic it may have a better
chance of floating.
Thalos and yellows are notorious for having aggressive tint strength. If you
have to use acrylic paint, you might have better luck going with the
Ceramcoat-type craft acrylics for a look-alike Thalo that have a lot of