Reprints of this can be affordably purchased on Ebay. This manual is full of reviews from trials as well as suggestion for use from the company. I wanted to highlight a few useful points from this manual for you. The below text is directly from the guide.
To clean the arm, relieve the lever key from pressure, by throwing down the lever guard, and then take out the key, which is replaced, with the guard in the same position. Remove the slide and dissolve the hard substance with water if any has collected in its cavity, taking care not to use any metallic tool in the operation, by which the slide, or gas-ring, might be injured. The bore is easily washed, or cleansed with a wet brush, after which, wipe it dry, and oil it, and the slide with sperm oil, tallow, or other pure oil, free from salt and acids.
Author's note: Good luck finding Sperm Oil these days. This was a common lubricant for firearms and machinery and is found in military manuals at least into WWI. Tallow, however, is much easier to find. I actually have a can of McQueen's Pure Mutton Tallow, and you can find it on places like Amazon. Just follow the link. I haven't used tallow on my Sharps or any other firearm for that matter.
In Loading Sharps' Guns, clasp the arm in front of the lock with the left hand, throw down the lever guard with the right, and insert the cartridge with the same, pressing it forcibly into seat in the bore; then draw the lever smartly to its position, thus cutting the end of the cartridge. Incline the arm to the right or left to throw off the superfluous powder from the groove on the top of the slide. Let the hammer remain down while loading, and never open the breech whilst the arm is loaded, without dropping the muzzle, so as to bring the barrel to a vertical position.
The Proper charge for Army Rifles and Carbines is 55 to 60 grains of powder of 300 yards eprouvette range; and cartridges are used for convenience and celerity in firing.
Author's Note: Not everyone knows that you can use the Sharps rifle with loose ammunition. It's mentioned in the manual:
In using loose ammunition the barrel must be held vertically, with the muzzle down, the ball is inserted and forced to its seat with a short rod, and the powder charge is poured upon it, and the slide closed. In all firings without patches, the balls must be coated with tallow, to prevent the bore from leading. (Italics original)
Interesting note on cartridge construction:
Cartridges made of the exact length of the chamber, having their ends closed with thin muslin or gauze, are preferred by some. Such cartridges are not cut off; the fire of the primes penetrating the cartridge through its rear end.
This is the first time I've read of gauze as a possible cartridge material. It's probably something I'll be trying in the near future. This goes to show, that original source material is out there. As living historians, we don't always have to rely solely on war accounts for our information. I hope this research is helpful to you.