In a boat I rigged, I used an aluminum pedestal seat base I had laying around to make a nice, stable mount for a 93SV. Super-solid, free, and there was really nothing to make, besides screwing a piece of cutting board on top:
It's what I had laying around, but I would consider making one from a typical Swivl-EZE seat base. It would still be sturdy, but could be taken in and out and has adjustable height for standing or sitting. Like this one: