I usually start out with 75 grains on a .50 cal.since Ikeep a 75 gr measure tied to the shooting pouch.
I try to find a bullet that performs well with that charge, then I can adjust up/down and see how it shoots. For a sidelock I just like loads in that range. Usually easy on the shoulder and still enough power for most of the hunting shots I get (my average shot on deer is probably not much over 50 yards and my longest shot to date is still under 100 yards). I sight in dead-on at 50 yards using the top of the front bead as my aiming point.
Some times I wonder why I even own an inline! I've spent hours and countless $$$$ getting one to shoot out to 200 yards, then stalk to within 50 or 60 yards before I shoot a deer. [&:]