I welded the base out of 2x4" steel tube, 14gage.
The leveling feet were purchased from mcmaster and have a 3/4" 16tpi thread 3" swivel pad
The machined aluminum plate is milled from a 3/4" plate. The central region that the equatorial head pivots on for latitude adjustment is 8" in diameter.
This picture shows the equatorial head mounted to the tripod. The fork arm will place the CG of the system over the middle of the tripod footprint, maximizing the stability of the mount and scope.
The mount will be anodized and the tripod will be painted once the system is fully tested and I am happy with the performance.
Machining the 6"x6", 1/2" wall, box beam tube for the fork arm. There was a fair amount of bow in the extrusion that needed to be removed via machining.