well in revisiting tony's method he really is only changing one thing at a time. he is doing seating depth testing over a range of powder charges. if there is a node in that range you should find it. 12 3 or 5 shot groups. now if the node is outside those charge weights or seating depths i guess you start over.
not so different then finding a charge weight and then doing seating depth test.
not so different then finding a charge weight and then doing seating depth test.