TOPIC: 1959 Redfish

I just purchased a 1959 Redfish Shark with a 196- Merc 400. It is in poor shape, no holes but the fiberglass cloth is visible in places and the fiberglass on the inside of the transom is thin and tearing. I know I am going to have to rebuild the transom. The motor will turn over but the linkages are frozen so I haven't been able to do a compression test. I removed the control cables and the control box works it is kiekhaufer but different.
My questions. I currently have a different 59 boat with a 400 Merc , has anyone done twins on a red fish? How much space is required on the transom since I need to redo it any way? Also what is the best way to do the fiberglass where it is showing the cloth?