So my question is how thick should I make the plywood? We have a 4 stroke 9.9 merc. Plywood that is on there now is two pieces of 3/4 laminated together on the inside and a small piece of plywood on the back that gives a final thickness of 2". Do I have to be this thick? I have no idea how thick the original transom was. Would it be o.k. to use two pieces of 1/2" laminated?