I have an M4 too. Great little drift boat!
My take on the M4 Solid Floor Mod. I used 0.625” Fibreglass Faced Aluminum Honeycomb Aircraft Flooring. Way stronger than Plywood and about 1/4 of the weight. In fact it is lighter than the stock slatted floor. I made it a 4 piece.
Great! I bet a lot of M4 owners would love one. The problem is, it’s a $2000 Floor in a $500 boat! Working in aviation has its privileges!