Since 25 yards was not in the mix I voted fifty, but use 25 to pull a 5 to ten shot string into the bull, then move it to 100 and dial in that load. Any subsequent bullet/sabot or powder/charge size shot I just shoot and pay no attention the where they hit outside of the bull. Once a subsequent load/bullet has been settled on I dial it in to hit the bull at 100.
All of my long inlines are shooting dead nuts at 100. I shoot other bullets and powder at the range but, again, let the bullets fall where they may and make no scope adjustments for them. Come hunting season I run two shots thru any gun I plan to take in the field to verify everything using the powder/bullet, sabot and primer the gun was zeroed at 100 with, then go hunt.