MinnFlyer, I'm with you on the glass. Haven't used it for covering in some time. I now prefer polyester. First tried Sigs Koverall, But it took too much filler to close the weave. I now use stits polyester, much, much tighter weave. Usually two coats sprayed on fills the remaining weave and it's ready for paint.
And with all your experience, I have a feeling you know the answer to your question before you asked. LOL