I'm installing a Mitchell OD and I cut up some all thread to make three studs to press in the pinion assembly using the torque tube. When bolting the OD torque tube on, I used two of the studs as guides while juggling things to slide the shaft coupling over the OD gearbox splined shaft. Made the solo work a lot easier.
In an effort to pull the pinion in square, I was eyeballing the gaps, but then used my vernier caliper to get closer-to-equal gaps. One tire was kept off the floor to let it rotate as the pinion engaged with the ring gear.
I left the rear spring on the car (with a spreader) and it was good because then I found out how worn the probably original shackles were.
