I'm usually with what Creedmore shooter said on the one load per gun. Find a good load that meets your expectations for that rifle and intended purpose and go shoot the crap out of it. I know plenty of guys that spend more time dealing with tinkeritis, trying to get that small margin of extra performance, than actually shooting as the rifle was intended. Nothing derogatory towards you if you're that guy as I understand the mentality, however I like to "get away from the bench" as much as possible. On the flip side of that, it isn't always economical (for me) with some of the big boomers. That would cut the amount of shooting I'm able to do down by quite a bit.
Two examples:
My .338 RUM shoots best with Hammer bullets, but they aren't cheap (I understand why Steve, again nothing derogatory intended). So I will load up some "cheap" bullets with a somewhat similar BC @ the same velocity and pound the crap out of some steal. I'm not working on the rifle, I'm working on me. Then load and check the Hammers again before season.
Same thing with my Snipetac with my "hunting barrel" installed. The bullets I'm hunting with are well over $2 per and the Sierra Matchkings (with the same BC) are well under $1.
Back on topic:
I was really hoping the Nosler LRAB would work for me. It has a decent BC, bonded core, lower velocity threshold, and not really high priced. However I have tried them (.308 diameter) in a half dozen rifles (a few that shoot exceptionally well) and cannot get them to shoot consistently.