Gentlemen, I NEVER shoot a double rifle [or any other hard kicker] off of a bench when developing loads. There are no benches in the field. Not only is it hard on your body the rifle recoils differently effecting the results.
I shoot iron sighted rifles kneeling at 25, 50 and 100 yards. I also shoot sitting at 100 yards.
After I find the right load I shoot standing at 25 and 50 yards.
With scoped rifles I do all the load testing sitting at 100 yards. Then when I have the best load I shoot it standing and kneeling at 25 and 50, and kneeling at 100.
I do not even test or zero my long range rifles from the bench, I shoot them prone off of my pack.

Benches..... we don't need no stinking benches.