I have a 3x8 ft X 2 in thick wood bench with 2 sheets of 3/4inch pressboard and a 1/4in sheet glass sheet on top for 3+ inch's of wood
this is supported at 3 places. the glass is so you can put plans under and build on top or just build on top.
I use a razor to clean/scrap the excess glue or whatever off. just dont drop anything heavy and hard on the glass.
I have been using this for 10+ years so far without breaking the glass.
The glass also works to cut material on, covering, balsa, foam, glass cloth etc.

Hope this helps,

Tony