Hi Bandit

I think 3mm for the main deck is too thin, make it 4mm with glass, but also check the class rules there might be minimum thickness, good chance you'll lose some weight but I'm not sure how much. Original plans for the Mosquito had two layers of 4mm ply, and back then Gaboon ply wasn't around, so I'm sure theres some savings there if you replace with Gaboon (Okoume)Ply.

Regards