I was hoping someone with a Sharps would chime-in but it doesn't look promising.
If you know the specifics of the load you are using, velocity, ballistic coefficient of the bullet, enter the information in a ballistic calculator and print-out the results so you know the drop and wind drift of that load. Here is the one I use to make my drop chats.
Hornady Ballistics Calculator
Then adjustt your sights to the lowest setting, put a large piece of cardboard at the 50 yard mark. Shoot once and if you can see the hit, then adjust the elevation accordingly... up to raise the point of impact, [POI,] and down to lower it.
Once you are close at 50 yards, move to the 100 yard mark and get the setting correct there. When you do have it set right, make note of where the sight is.
Then your ballistic calculator will tell you how much you need to adjust up for the higher POI at 200 yards; set it then move on to 200. It may or may not hit properly on the first shot, so adjust accordingly then note where it is set.
The same goes for 300 yards, as does 200. Make sure you note where the sight setting is for future reference.
I hope this helps; if I had a Sharps I could be a little more specific.