Hi Bruce,
Do you have a tipper or slider? Easiest place to mount it is between the main panel and sub-panel on a shelf that you'd build (behind one of the screens for easy access). The neato thing about the GSU is that you can orient it whichever way is convenient for access/maintenance. Anyway, drop me a line and we can give you some suggestions based on what we've done.
Cheers,
Stein