Ken said that NCWW will be demonstrating at an AAW event and they have standards that have to me met (I think it's in Raleigh, June or July 2019).
The AAW links that Dee2 provided describe Lexan safety shields that are 24" x 36" x 1/8" and Phil is suggesting 30" x 36" for our NCWW lathes. We may not have much leeway to play with the basic design.
1/4" thick is what I read in both BoMs, FWIW.