To be honest I have had excellent results with 147gr campro (yes campro) backed up 42.5gr benchmark with WLR primers in RP casings, this keeps me sub moa. This also takes me ou to 700 yards easily.
There is no such thing as a "best" load. There are all kinds of trade offs in every choice you make. Shooters tend to be quite conservative and thus will cluster around generally held beliefs. There is no reason those beliefs are true and most shooters will never experiment to see if they are.
Heavier bullets cost more and will generate more recoil.
Personally I have had great results using 125gr Ballistic Tips in my 20" 308 all the way out to 800 yds. These bullets are fast and flat and don't generate a big wallop on my shoulder. The combination of the Nosler 125s and Varget produces 5/8" 5-shot groups for me.