Welcome to SBO. Always good to welcome a new member. There are a few ComPac owners or past owners on here. We are all happy to help in any way we can. You have picked the best sailing forum on the Net. I'm sure you will get what you need here and a lot more.
I don't have a ComPac, nor have I made a cover for my companionway, but I remember touring the original CP23 Clark Mills plug at a boat show in Tampa, when I was a kid.