Degreeing Cam by Measuring Overlap @ Lifters

How would ya do that? Keep pulling it down, after a comp check, adjust, reinstall, measure again? Sounds labor intensive, maybe there is a short cut I'm missing? Or maybe it's just old school work ethic, where if you want every bit of performance out of that mother you're Going to keep into it, till you just get it right!
I've never done this but I assume you just jig it up with a bell and starter, and just put in the no1 pushrods and go to it. I can see you could do it fairly quickly. I don't know enough about cam design to know whether or not it is a definitive marker, but I've read of guys doing that and claiming so.