I’m working out of town so I’m going by memory here so don’t fully trust what I’m saying but this is the gist of what I did. (Tom Wood’s website has great information on everything and you can always call them for a quote and they will talk you through everything) I don’t know what you mean by clock the axle?
I installed a Sterling rearend, I had to change the spring perches, so I was able to set the pinion angle at whatever I needed it to be.
1- set the van on level ground, make sure you have the suspension and ride height where it will be when when final, set all 4 tire pressures the same.
2- with a angle finder find the angle of the yoke on the transfer case. (Write that down)
3- set the pinion angle on the rearend (from the yoke) to match the angle of the transfer case yoke angle. You want the two yokes to be inline if you are not running a double carden. I was told as long as the driveshaft is at 10° angle or less (measuring the angle of the actual driveshaft on the driveshaft itself) you don’t need a double carden. (Going by memory) to measure the driveshaft angle install a old driveshaft and put the angle finder on the driveshaft, or run a string from yoke to yoke (making sure to go from the same place on each yoke) and measure from the string, or run a bar from yoke to yoke (making sure to go from the same place on each yoke) and measure the angle of the bar. Or what I did was measured from the ground to the center of the transfer case yoke (wrote those numbers down) then measured from the ground to the center of the rearend yoke (wrote those numbers down) then gave those measurements to Tom Wood’s and they did the calculations and figured out that my driveshaft angle was under 10° and that I didn’t need a double carden in the rear of my van. I hope this helps.
http://www.4xshaft.com/JR7_TW_Driveshaft.pdf