On this and other accuracy forums I would guess that all that most shooter/reloaders use a manual for is a safe starting load to begin a pressure test with. Personally, the first thing that I do with a new powder is to do a one shot per load pressure investigation, with bullets a little longer than touch, starting low, and working up in increments based on case capacity. For a PPC sized case, my increment is .3 gr. I keep increasing the load until pressure signs tell me to stop. I FL size my brass for each shot. When I see a little more pressure than I want for my top load, I note the previous one as maximum for that ambient temperature and humidity. I do this loading at the range. I do this shooting over flags, on a day that has shooter friendly wind, on the same target, with the same aiming point, noting where each shot prints. This usually gives me a bonus of finding one or more clusters that are the basis for my two three and five shot tests. Generally I use a bullet that has proven accurate in the rifle with other powders.