What's safeWhat works best?

I'm more than just a little concerned regarding some widely divergent loading data. I'm loading match brass, Accurate 4064 powder and Nosler J4 Competition 168gr. hpbt bullets.

This data is for the same 168 grain hpbt bullet.

AccurateArms.com suggested Max load of 43.0 grains of 4064=2571 fps (24" barrel)

Accurate 2001 Reloaders Guide . . . Max load 42.5 grains of 4064=2601 fps (24" barrel)

Sierra lists 44.7 grains of 4064=2700 fps
Sierra also lists 41.4 grains=2500 fps as an "accuracy" load.

Lyman's 46th edition . . . 45.0 grains of 4064=2717 fps (26" barrel) as "potentially most accurate load" :sniper:

Anyone out there as confused as I am?
So what's safe in my NM M1A?
Anyone load any of this Accurate 4064 under a 168 gr. hpbt?
If so, how much is safe? And what load was most accurate?
I'd appreciate any and all the help I can get.