After doing some research, it appears that U-Joint is no longer producing their single Sienna seat mount. I really liked the versatility of the single seat option.
As of 2023, is WeldTec the only game in town with their side-by-side mount?
So I bought Sienna seats and then realized how hard (expensive) it was going to be to get a bracket. The weldtek one is great, but by the time it gets to my house in Canada - 2K...
So out of necessity, i ended up just figuring it out and currently in the middle of fabbing it up and will get it powder coated. 1/4" Aluminum base plate and steel Angle (can't remember thickness i got). Will definitively be stout and heavy.