20 Transom Rebuild

[EP]

I am in the process of replacing my transom. My project is the same as hammer's 20 on the picture section. I have cut all the old transom out, replaced the core with new marine grade plywood that is glued and screwed into place, and i have attached the outer skin. I am ready to glass the seam but.. I am worried about the strength of that seam considering the wood and fiberglass skin were cut in the same place. Is the lay up of glass enough to have confidence that this transom is strong enough for my new 150? (my cut out is the exact same as hammer's) I have thought of two options to make it stronger: 1) Drill through the top of the transom down 10 inches and insert a stainless rod to connect the old plywood to the new. 2) Make a stainless backing plate on the inside liner to hold the new transom in. ( the not so clever solution or desirable) So here is what i have thought of What are your opinions and experiences? Thanks Eric