[RidgeRunner]

Inside transom thickness from the factory on my V was thin (One layer of heavy woven into one oz matt). They didn't throw too much at it and they didn't spend any time filling in the gaps with putty to smooth out the transitions. To me 38 oz. sounds about right with what the factory used. I don't recall them using much if any reinforcement around the perimeter where the real loading is. The outside (hull) on mine was about 1/4" to 3/8" thick. You could debate for hours on the layup schedule. What Richie Rich said, thumbs up!! I personally like to layup wet on wet if two or more layers are used. If the 1st layer is allowed to kick off and set, you then have to grind it out again to get a proper bond(at least with VE, not sure about epoxy). So you would be grinding away some of the long woven strands in order to layup a second layer and that would deminish the strength of the first layer. When wet on wet isn't possible and where weight isn't a concern I like to lay a layer of 1.5oz mat into the roving as a sacrificial layer that can be roughed up for the second or third layers of glass. My .02
IMO what you have done so far looks great. You need to spend some time on the top of the transom to ensure it is waterproof. With respect to the heavy weight fabric, it is very difficult to get it to make the tight radius where the upper edge of the plywood core meets the upper lip of the transom. You may want to get some lighter glass to reinforce the edges and push into the corners at the top sides and bottom of the transom. You have come a long way fast. Don't rush it too much, take your time and the results will be spectacular.