Yes, the reticle can definitely be used on a .308 platform.
Yes. In the instructions the is a table that directs the owner to zero the scope at +1.0” at 100 yards when using M80 147gr at 2650-2700 fps, and the same +1.0” at 100 yards with 168gr SMK at 2600-2650 fps. There are also 100 yard zeroing recommendations for various loadings of .223 Rem, 5.45x39, 6.5 Grendel, 6.8 SPC, as well as 5.56 Nato.