I shoot a lot of 308 and always start my load .5 under mid range load to .5 over mid range seat at 0.018 -0.022 off the lands and save some $$$ and use Sierra 150gr. match kings, CCI lr primer and you will be good to go.
Also never change more than one thing at a time because you will not know what worked.
I don't bother with ladder groups or OCW I start with 3 shot groups at different loads and go from there, but when done always verify with 5 or 10 shot groups.