Jeep Cherokee Rear 8.25

so when you guys weld up your perches, do you use a jig, or do you just eyeball it? I was thinking of using two 4x4 wood blocks, pull the old axle, set the blocks under the perches to get my initial measurement, drilling a hole to put a stud in each block then using that as my template to get the new axle welded.. should keep the perches level with each other and straight...

Kinda hard to describe, I can draw it in my head lol