Per Frogwatch:
Been there, done that, it works. I would not worry about melting the
styro.

Just did it. Stuff has pretty much gone off and, as you say, no
problems.

Which begs a question:
Given an area about 3" in diameter that I will glass over -
feathering from the edges into the 1" hole in the center -
intuitively it seems like I should layer the glass with a small
patch in the center first, a larger patch over it, and so-forth
until the last patch covers the entire area instead of
vice-versa.

Seems like I'm aiming for a situation where, as much as possible,
I've got a single contiguous hunk of glass over the whole thing.

Does this sound logical?

I ask because I can twist it around and rationalize the opposite
too...
--
PeteCresswell