Tuning matters, so keep that pursuit active. As not much more than a semi-illiterate novice trad archer I have found myself in similar straits. I have some 500s that are decently tuned for my 45 - 48 lb bows. I also picked up some 600s as a sanity check on those same bows as my draw length and the bow weight puts the arrow selection on the edge of the selection charts.
The 600s didn't help that much on the 45-48 bows, however, they turned out very nice for my 35 - 40 lb bows. Tuned by Lady Luck, on my 40 lb. Bear #3 T/D limbs (A riser), they shoot like a .22 squirrel rifle, or as close to that as I currently shoot.
Until I stumbled onto that combination, I was fully in the limbo land where consistency and accurate do not coexist. Bareshaft wasn't really showing me anything consistently different, I could 'sometimes' group 3 and too, I got to the point where if I pulled or pushed the shot, I was aware of it.
I got out the video camera for form observation.
Oh duh.
Shooting close at a ground target, I'm standing straight, bow arm is pointing down to the target and my string arm is pointing up at the clouds. Squaring up the back and arms and then bending at the waist helps. I continue to battle the bad habit, but keeping that part fixed is helping Mr. Consistency.
The video also let me look at my release, which seems decent enough, and my follow through... which.. no. No, it does not look at all decent. Does, or did, is being worked on. It is now another point in my 'sequence', after the release, to ask 'self', "Where is the bow pointing?"
I probably still have some things to fix with what's going on the string, but I have more, bigger things to work on behind the string.
Set up the video to see how you are doing, it is a little surprising the difference between what you think and what you are.
G'luck
Nick