Sound wisdom from Daryl and Taylor's approach - no doubt about it.
My approach is a bit different and perhaps unorthodox, but it works for me because of where I live (4000 ft above sea level & very low humidity in the Summer months). I also use to shoot a lot of long range gongs at our local Range out to 200 yards.
What I found that works best for me (and this is just me), I use one charge in my .45, (though here lately I've been experimenting with other charges), but,,, for me and 200 yards - one charge (65 grains - 3fg).
According to the Lyman Black Powder Handbook (put together on the east coast at around 800+ ft above sea level & high humidity) - my load should drop 48.53 inches... It doesn't. My load drops in the neighborhood of 24 - 28 inches.
Therefore I know my target is 28" wide so I just try to hold over the target the same height as the target is wide, (sometimes I have to hold a bit higher - but if my first shot is on, I can judge from there where to hold). I shoot windage and elevation best guess and most the time it'll get me on paper. Not the scores that Daryl and Taylor are getting, but when shooting a 200 yard - 24" gong it doesn't matter where the ball meets the metal as a hit is a hit.
Same holds true for the paper target, but here points do count, though I'm more concerned of just getting as many rounds on target rather then what my final score reads.
Good advise Daryl. Thought I'd just offer up how I do it out in the center of the U.S.A., (or close to center)....