ply/glass vs foam/glass for a cockpit floor

Hi,
Am in the process of renovating an 8M trailer sailer and was thinking about trying to save weight where possible.

wondering what material I should use for the cockpit floor?

options are:

9mm ply sealed on the bottom glass on top - strong but heavy?

6mm ply glass on bottom and top - maybe not strong enough??

12mm foam core glass top and bottom - strong enough?

would there be any significant weight saving in going with foam?

would foam be impact resistant enough for cockpit floor?

would I have to add a couple layers of glass on top?

any advice much appreciated

cheers

 

I have used 15mm foam in a powerboat, and impact resistance is only a problem if you keep dropping anvils on it. Probably had about 3mm or so of glass on top, half or a little more underneath. Made it in one piece about 20 feet long, up to 7 feet wide, then glassed it in. That may not suit your application.