Pete - Glad to see you made it over. As Big said the drain scuppers have a lot to to with the "sinkcraft" name.
Also plenty of 20's were made with 20" transoms because that was the technology of the time.
If you could find a 20 with a redone transom and redone drains you will be ahead of the game or look around the site and see how to build your own.
Welcome to CSC!!!!!!