The red circles in the top view represent holes for the seat base. I cannot measure diameter or spacing because my seat base is still bolted to the riser. You can determine that from the seat base you will install. The back wall of the riser also has two horizontal holes on each side to mount the seat base, also not possible to measure without further disassembly.
The 3-1/4 measurement seen in the top view is the inside distance from the front of the riser to the parallel brace that goes the full width of the riser and merges with the curve at the front. The brace is even with the dip in the front of the riser, as seen in your photo. From the side view the 2-7/16 measurement is the height of that brace (it is off the floor and bottom of the riser). That 2-7/16 is not the height of the outside of the riser. It appears to me this brace, while important, is not critical in it's dimensions, as long as it does not extend beyond the outside of the riser or interfere with the shifter.
The rest of your drawing seems correct. No $ or beer necessary, just help another member sometime.
Kent
Last edited by Lightholder's Dad; 03/04/2019 12:43 AM. Reason: clarification
