Terry
That's a bit of a "piece of string question"
The microbaloons are light but weak, and the resin is dense but strong, so every different mix is a combination of these
It you want a sort of "varnish" coat, you need just enough baloons to make the resisn cloudy
If you need a really "filler" material, you put in enough to make a good paste which won't slump
I think your answer (to fill the weave of a finishing glass cloth) is mix in enough to make a single-cream consistency - still brushable. Paint or scrate it on very thin, sand and be prepared to do it again
andrew
