it should work fine.
3/8 may be a bit thin, but your too close to let me scare you off.
1/2 definitely works with 4 oz glass.
however, the whole idea of plywood is
is getting good, fast and cheap all at the same time.
so i would shy away from the top shelf items
okume...go for home depot luan
s glass....stick with normal e stuff.
resin research....maybe west or 3m is cheaper (or polyester but it gives me headaches
even cheap plywood can carry more load than good foam, so just use enough glass to carry anticipated flexure loads. (sometimes voids in the wood become an issue but this is cheap, right)
if your want to limit additional weight from too much epoxy, spread a thin coat on the wood before glassing. scrape most off and let it start to kick (judge from some scrap)
then add glass and laminate as planned.
start with the 4 oz per side.
let it cure and test the flex.
if you want more stiffness:
wash lam to remove blush, scuff surface and wipe with alcohol.
add another 4-6 oz per side depending on results.