My suggestion is increase your powder charge when shooting patched R-ball also try a thicker patch either .015-.018. Doing both will help flatten out the ball trajectory's arch some which drops point of impact seen down range on paper.
Did you happen to fire one or two balls down range to check-out your rifles accuracy at the 100 yard mark under its now (4" high) circumstance?
OP you may find your rifle actually near bulls-eye at that further distance in its current behavior. Perhaps with a little left-right movement of your rear peep may indeed prove beneficial at that distance instead of 50 yard targeting. Next time you get the chance to head over to your local practice Range. Shoot the 100 yard distance first without changing a thing just to see how it does at that distance with patched ball.
I myself have a Renegade and found it to be as accurate as any of the others I have available to me in 54 cal. Well with one exception in after thought. I have a 54 cal White Mountain Carbine that couldn't hit a closed barn door at 50 paces. Talk about a useless rifle. But that's a whole different story for another time. Good luck with the Renegade Striker1.