This was a kind of weird process, we had to put a bolt through the plate to make sure it held the caliper at just the right spot so it "hovered" over the rotor at an acceptable height, as well as at the right angle. so what we did was put some thin wire around the OD of the rotor, then sat the caliper on top. It was now "hovering" above to rotor at a uniform height. With the spacer on, we pulled back the wheel as far as it could go, and got the red mock up dots over top the mounting holes the best we could. The actual mounting holes for the caliper were quite tricky because we could not go through the back for the bottom one due to the rotor pattern and wheel straight up blocking it. The old shock mount was right in the way for the front as well, So we ground it out, but it was a tight spot and we could not get good visualization on where the hole really needed to be. Even for the top bolt hole, the rotor blocked most of it from the back. We ended up eyeballing it from the front, figuring we had enough meat on the bracket to pivot and adjust the caliper to get the bottom just right and keep it even.
When we got it where we wanted we clamped it to what was left of the swing arm shock mount (oh yeah, I chopped all the material we did not need off the old shock mount so it looked a little nicer) then drilled through the old shock mount and the plate as far back as we felt comfortable. Then we placed the wire under the caliper again and drilled the top mounting bolt for the caliper, this was eyeballed but we got it right where we needed it. The red marker dot was a guess reference from when we were shaping the plate, but ended up being damn close.
You can see in the previous photo of the mount and caliper together, that hole is already there because I forgot to take one of just the completed caliper mount. We used a plasma cutter (because why not) to make the hole in the shock mount into a slot so it could be adjusted forward for chain tension. (even though it cannot make much forward movement because of the tire size rubbing the front cross bar of the swing arm). Lastly we welded an M8 nut to the back of the plate.
We mounted it all back together with the bracket bolted in place to the swing arm. With the top caliper bolt in snug but not super tight we once again placed the wire between the OD of the rotor and caliper. When we got it exactly where we wanted it, we cranked down the top bolt. and took it all back apart. Now the caliper was sitting on the bracket exactly how we wanted it, and was held in place tightly by the top bolt . We then used a punch to center the bottom mounting hole for the caliper from the rear.