I finally separated the halves and removed the strongback.
This was much more difficult than necessary. The stern area lifted out fairly easily, but of course, some glue found a way to cement the bow together. Afraid to use too much force, I decided on the spot never to use an internal strongback again, and sawed the bugger in two. It still seemed to weigh a ton.
The culprit. I wiggled, juggled, and went at it with large drill bits, until it came free.
The OI was built with wooden internal stems. I think they are a good idea, giving you something to glue the strips to. Here, I had to use a significant fillet of epoxy & microbaloons. I also used Fairing Filler on some of the gaps & low spots.
Again, I found it easier to 'glass the bow & stern separately.
After glassing the rest of the interior, I used these spreader sticks, as per the instructions. They're are supposed to prevent the hull from shrinking when the epoxy shrinks. I hope it works,