I read through the thread and was going to chime in, but
@CK1.0 already said it all.... focus should be on the shooter skill development and not the load development.
A lighter 308 is hard to shoot well, and often times certain equipment/components are only going to shoot so good. If you've got multiple 3/4" groups in a row I would personally call the load development done.
However I get that load development can be a fun exercise and if that's what you enjoy about shooting then keep doing it. I would just focus on coming home from each range trip with as much analysis about yourself as a shooter as you have analysis about your groups.
Video yourself close up with an iPhone in slo-mo mode and analyze the footage... are you blinking? Anticipatory tensing/movement? Does the rifle recoil look smooth and your body look relaxed? Did the reticle end up in the same place every time? Stuff like that is why we miss targets, not ES/SD.