I did mine on jackstands (with the exhaust off the car since I had also just finished a clutch job) it was fairly easy to install however the problem I had was that I either had to have the car in gear or have the parking brake set to torque the bolts on the flanges. So I had to put the shaft where I wanted, shimmy out from under the car, set the brake, shimmy back under the car, torque the bolt(s) I could reach, shimmy back out and take off the brake, and repeat. It was a pain in the ass but a good full body workout, would definitely be easier if you had someone to put the car in/out of gear for you.
Also worth noting, I had to chase all the threads on the axle flange to clean out old loctite, it was making the flange bolts for the DSS difficult to turn in to the point where I was afraid of stripping threads and it definitely would have skewed torque readings. The transmission flange seemed to be OK.