Transom repair???

[jetblue319]

I was wondering is it better to remove the back skin of fiberglass on the transom and then the rotten plywood and replace with Coosa Board and then reglass? I currently have everything remove on transom (engine, platform) except the new tabs I installed. ( have to fight that 5200 on the trim tabs and drain plug. I signed up for a West End fiberglas workshop in February. Again thanks for the inputs
Jet