85 aluminum-hull Seacraft with bad deck

I'm a newbie here, found this forum via a Google search. A buddy and I are rehabilitating a 1985 aluminum-hulled 21 foot Seacraft center console. The decking is trashed due to extensive rot: Years of PO neglect plus non-structural open cell foam on which the original plywood deck was sitting. When I walked on it today it "squished". Also, the foam acts as a "dam" and prevents water from flowing to the aft end and the bilge pump/drainage plug.

We demo'ed the front half of the deck today and will tackle the aft end tomorrow.

Question:

Can anyone recommend a better material (than marine plywood) for the replacement decking/sole? There seem to be plenty of aluminum stringers there to which we can attach. My thought at present is to use a minimal amound or wood and try to find a decking material that is truly waterproof, like aluminum decking or even perforated metal sheets that will let water enter the bilge, flow back to the stern and be pumped out or drained while underway. NOTE: primary usage will be at a N Ga. lake and the boat will be stored in a boathouse.

Any suggestions? Ideas? Links?

Thanks so much!

85 Seacraft in Atlanta Ga.