The 'target' Taylor and I used, was a light coloured, whitish looking rounded rock - about 20" in diameter, that projected out of a 12' wide x 12' deep "V" of black dirt, on the side of "The Chief". The whitish rock was in the middle of the V and was easily seen due to the black dirt around it - a perfect aiming point. One merely held up enough barrel over the rear sight, puts the blade on the centre of the rock and fires. The angle to the rock was about 30 degrees, I'd say, from the flat ground of the range. The Chief is a granite face, very shear - the type that rock climbers like, & seem to fall from, every year. It is part of the coastal mountain range that stretches from North Vancouver, BC, up into Alaska and South to California.
With naked eyes, hits on the rock appear as dirt splashes right on the edge of the rock. With glasses you would see the ball in flight the last bit of travel, dropping onto the rock from above(that's the appearance), then deflecting off the tock to splash into the dirt at the side of the rock. Initial hits as low as about 8' or as wide asperhaps 6' to either side were easily seen in the dirt and you could walk the 'hits' onto the rock quite easily by increasing the amount of barrel over the rear sight or holding windage for wind.
Taylor's .62 Hawken had a bright spot on the barrel from leaning it against the bench. This light spot just happened to give the proper elevation for his right with the 120gr.(or more) powder charge he was using at that time.
We were both young then and had good eyesight. At times, we could hit the rock almost every time. At that time, 1974 1975, we were using balls that were .005" smaller than the bore (same as today) and denim patching that was .022" thick, with spit for lube. We found that basic combination worked in every rifle we've ever had - right to present. We only needed to finalize the powder charge to find the 'best' loads.