As a WAG I would suggest:
For "high tech"
3mm marine plywood with ~6 oz fiberglass/epoxy on the outside and 2 layers of epoxy resin on the inside
2mm Carbon epoxy either use prepreg or vacuum bag to the highest delta P you can. If you are testing impact resistance, make up a sample with 1 additional layer of Kevlar 49 near the middle. This will reduce crack propagation.
Extreme High Tech
2mm marine plywood or 3mm cedar strip with 6 oz carbon cloth on the outside and 6 oz kevlar 49 on the inside, Epoxy hand lay-up
For production
2 layers 8 oz fiberglass cloth on the inside and 2 layers 8 oz fiberglass cloth on the outside of 4 mm marine foam core. 2 samples 1) Polyester resin, hand lay-up and 2) epoxy resin vacuum bag @ 10-15 mm Hg
3-4 mm Fiberglass/polyester, hand lay-up
Find broken production catamarans. Cut section from the side of the hull in front of the front crossbeam.
This is a guess, but it is probably not too far off.