I just saw an ad by a powder company (Ramshot maybe?) that had 4 different powders in a 1# pack. Now, if you figure loads you'll get maybe 150-200 rounds per pound (rifle). I suspect it will take that many anyway to see if a given load works using different combinations of bullets, primers, charge weights, seating depth.
As above, get recommendations. I asked one of my friends that shoots high power about a load for my AR. Used his rec's and my first two groups were about 1/2". Disclaimer...I don't shoot or load near as much as some guys on this or other boards..that said...
In the final analysis I'm not sure that it's all that critical in a number of applications. If you have 4 different powders with nearly identical burn rates, I suspect that you'll get acceptable accuracy from most of them most of the time.
If you think that's not true, why does one guy swear by 4064, another by VV, another by 4895, and they're all the same application??
I suspect bullet quality, seating depth, and run-out are as or more important than powder brand and/or number