I'll just echo what others have said, I put a tower on my boat last year and Monster provided backing plates that were just the size of the feet, about 2 1/2" x 2". So I made up additional plates that were about 10" long, also aluminum. I was able to get a piece about 2" wide 1/4" thick and 4' long from Grainger or something, it wasn't expensive, and it was easy to work with, didn't require a machine shop to make the plates, and I feel MUCH better about the backing now, than I would have with the tiny factory plates. I used it all last year and it feels extremely solid, I couldn't be less worried about the feet.

What kind of tower did you get?