CF wheelchair seat pan advice needed?

Currently I use 5.5mm non-structual interior grade hardwood plywood (from Wickes) for my wheelchair seat pan, it spans a distance of 350mm. On top of this I place my foam/memory foam cushion. The plywood gives me the right degree of rigidity/flexibility but adds more weight to my ultra-lightweight wheelchair than I would like. I would like to replace the plywood seat pan with carbon fibre or CF sandwich but don't know what type and thickness would give me a similar feel to 5.5mm plywood? I know some top-end wheelchair manufacturers give the option of carbon seat pans but I they're very rigid with little flex, especially for someone of my low weight. It doesn't have to one complete seat pan front to back, it can be slats.

NB: I weigh 53kg