Lynne,
Be sure to check the distance, on centers, between the SS guard. The newer Edson stuff is often designed for 9.5 inches, and if your boat has an OEM Yacht Specialties setup this will probably be 12.5" ...
Using the design of the commercially-produced ones, you might want to make your own. I believe that you can buy the hardware separately, and then fab up your own table top -- not sure where I saw hardware for sale, but the internet is a big store...
A friend of mine made his own table top, complete with fold-down leaves, out of smoked acrylic!
Best,
Loren