I have ended up using a combination of a ladder test, and then OCW to avoid shooting up too much ammo and components. I first shoot a ladder at 300 or 400 yards to narrow down the powder charge, then shoot 3 shot groups at 200 yards with smaller increments of powder charge. You should be able to determine if the load is good to go or not with about 30-35 rounds.
I do the same. I run a ladder to find my pressure limit and it usually will show me two differnt "nodes." Node being where they all tend to group together regardless of charge. Then I will load up a bunch of different 4 shots around that node and see which one shoots the best. Then I load up about 4 differnt batches of like powder charges and vary the OAL to see what my best seating depth is. Usually I stumble onto something that works. I just read a post where he finds his max pressure, then backs it off two grains and uses that. I may give it a try to see how it works? I am always trying to find a way to make the testing process quicker, cheaper, and more accurate. I know, what a dreamer I am!