Other than a joke about a suitable minimum for elk, I would suggest you pick the velocity you want to use with that bullet using that powder, load up one of each at some staggered charge, like starting at 70 grains, load one, then one at 71, and 72, and 73, and so on. Shoot them over a chronograph until you get your target velocity. Then duplicate that load. If you want 2150, you may have to get near the top end of SAAMI pressure for the cartridge to get there. If you want 2200, you may have to step on it a bit more. Regardless of Hornady's results, if you want to stick within SAAMI loading specs for the cartridge, trust the powder company more than the bullet company. In other words, if Western claims a top speed of 2159, chances are you are going to be exceeding top pressure level for the cartridge by at least a hair to get to 2200, all other things being equal (brass, primers, barrel length). Not that exceeding that pressure level won't be perfectly safe, but if you keep going up, at some point it won't be.
There can be lots of difference in the data due to use of differing lots of powder, which is why we are told to start low and work up. Some other differences would include the way Hornady works up loads in a pressure barrel, then shoots them in an actual firearm for velocity. Ramshot just shoots theirs in pressure barrels. Did both use the same length of barrel? That would also make a difference.
