I have never tried to work up a fast 308 load. I work for accuracy and what ever speed the bullet goes ,it goes. I chronograph only after I get satisfactory accuracy. I like to have all my 150 grain bullets in the 2675 to 2750 range, and near the same for 165s.
I like to see 180 go 2475 to 2550 from my 308s
If that for some reason seems as it it's not powerful enough I take out a more powerful rifle.
I I have 270s the shoot 150s at the top end of 2900 and one that touches 3000. I have a few 30-06 that can drive the same bullets as my 308s a bit faster with very good accuracy. (as if that mattered)
If even more is wanted I have a 358 Winchester, two 9.3X57s, a 9.3X74R a 9.3X62 and a 375H&H and a 404 Jeffery.
So I see no reason to hotrod any gun just to hot rod it.
If it shoots well with a hot safe load, that's great. My 25-06 and two of my 270s do just that,. But I shoot what seems to do well for accuracy with good game bullets' that don't break up badly on impact. I don't care about speed for speed's sake.
My 6.5, both of my 308s, one of my 30-06s and my 8X57 all shoot best with moderate loads and they kill things just fine. I have been doing it for a LOT of years and have learned that chancing more velocity just to make a bullet go faster is mostly a waist of time in the real world for hunting.
