Trigger pull must be isolated from rifle support. This can be accomplished by 'educating' your trigger finger, actually your entire hand, so that the trigger is activated with a straight back pull, no torque is introduced to the stock by your grip, and your grip does not change as you increase pull weight on the trigger. 'Lighter trigger pulls are more accurate' is only true because of the sympathetic nature of the human hand. Applying grip on one or more fingers will naturally apply grip to all fingers. You have control of this, but it is a learned behavior, and requires a lot of learning to make a meaningful difference in shooting. You must isolate your trigger activation from your rifle aim.