I have done pretty much every method under the sun. The only one I haven't done personally, but have witnessed done and been along for the ride with, is long range ladder testing on paper at 600 yards. The ladder method is how I would like to start doing load development, but I have to shoot in farm fields and I can't always go whenever I want. I have been doing load development at 100 and 200 yards the most. I do a modified version of OCW for powder charges and shoot a "Satterlee" test over the chronograph. I shoot 2 shots at each powder charge at 100 yards on a target that I designed and print off. I look for the same point of impact for 2-3+ loads in consecutive order and I look for the disparity in the two shots. I'm not really shooting groups, I am looking for a pattern with similar points of impact and I like to see the two shots either touching or no more than .2-.3" apart. If the powder charges string up and down a lot or there's no flat spots in points of impact, then this might be a sign to change powders. I shoot one shot each over the chrono with the same charge weights I test on paper. I look for a nice gradual increase in velocity for each charge weight. I am not necessarily looking for "flat spots" or "velocity nodes" by doing this test, I'm mainly looking to see where velocity is and how it's climbing as powder charge increases. Sometimes I see a correlation where my flat spot on paper lines up with a flat spot in velocity and that's a good sign but can also be a fluke. I mainly test velocity to see how consistent the velocity is changing from shot to shot. I like to see say 0-30fps increase per charge weight. I don't like to see one charge gain 30fps and then the next lose 20fps and then that's followed by a spike upwards of 50fps. I don't like to see up and down "spikes" in velocity. A nice gradual trend upwards to max pressure is what I look for. This tells you your powder, bullet, primer, barrel combination is working well together. If your velocities are jumping around a lot, then this would be a sign to change powder or primers.
After I find the powder charge I like, I will load up some rounds in the middle of that "node". Say 68.4, 68.8, and 70.2 was my flat spot on paper, I will load up 2-3 shots each at 68.8 and do a seating depth test. I shoot my seating depth test at 100 yards also at the same style target as my powder charge test. I look for the same thing in seating depth, 2-3 different depths having similar points of impact with bullet holes touching. With seating depth I like to see the shots print tighter "groups" than in the powder charge testing for at least 2-3 consecutive depths. You can do 3-5 shot groups when doing seating depth but I try to save components and have found "patterning" the different bullet jumps and charge weights works too. You can also repeat the test twice on different days and see if things repeat to get a better feel for the "nodes". If nothing stands out in the seating depth and groups are big, change bullets. I've chased my tail and burned up a lot of components trying to make a combination work that wasn't happy.
I forgot to mention, when I have a brand new barrel, I'll break it in with 100 shots with a mild load. During those first 100 shots, I'll do a seating depth test with that powder charge. Whatever jump works best with that mild load with be the seating depth I start with when doing load development. Then I'll re-test the seating depth with the powder charge I selected. I use .005 increments in bullet jump and start at -.010 off and usually work back to -.050 off. Sometimes I'll try more jump but usually I find something in that ballpark. This is my scale for how I select incremental sizes for powder charge
Less than 30gr max = 0.2gr increments
30-60 grains = 0.3gr increments
More than 60gr max = 0.4gr increments
Below are some examples of my targets and test methods.
