db,
Your Warnes will return very close each time you move them, but there will be a bit of variation. I tested that under very controled conditions and found that they returned very well but settled slightly after three shots, then stayed constant. Trick is to make sure that they are butted firmly in the front part of the cross-slot, so that they cannot be effected by recoil.
Accuracy in my shooting was within an inch at 100 yards. Variation was usually consistently in a given direction that seemed to vary with each rifle.
Have heard of guys lapping Warnes, not sure how well that works with vertically split rings. If nothing else it might reduce ringmarks from the sharp outer edges.