Ideally, the throat of your grip should rest on the meaty part of your palm between your lifeline and your thumb. No part of the bow should rest on the finger side of your lifeline. When you draw the bow, the feeling should be that the force of the grip pressing back against your bow hand is in line with the bones in your forearm (bone on bone contact), such that you don't feel like you need to exert any force to hold your bow hand in place or in alignment. In other words, the feeling should be that the bow is locked in place, not that you are having to hold it in place.
You should arrive at an ideal grip, which may vary somewhat from person to person, and then tune around that. Not vice versa.