if the action changes position with respect to the stock between shots a rifle not going to be accurate. There should be a comfortable region between where the stock is so loose it changes position with firing and so tight it warps or crushes either the action or the stock. What that range may be depends on the recoil , the stock material, and the stock and action design. I test my rifles by adjusting the action screws both a little high and low separately to be sure there's a zone where the adjustment makes little difference and it shoots well. I prefer to run the screws about 10 in/lbs over where the accuracy falls off from being loose but not to exceed 60 in-lb. (for a Rem 700 in a fiberglass or pillar bedded stock.). The screw size, action type and stock material all matter in determining what torque to use.
I never "tune" a rifle to purposely shift the barrel harmonics using the action screws. It certainly can do that, but it means the effective position that the action is attached to the stock is shifting with screw tension which it should not. It can of course do that with a poor bedding job or if the action is "bent" over the magazine assembly. I only use screw torque as a diagnostic tool. It's the bedding or inletting which should be changed if it's not right.
There's not much point in doing load development until it's been determined the barrel and stock aren't shifting. That's true for the action to scope interface too.
