I just knew, after reading the first part of your post, that you were a "F" class shooter, and your "Home Away From Home" is at 1000yards.
The reason I used "Windage & Elevation" instead of "Drop & Cast", was when I first started getting interested in shotguns the terms left me confused. The term "Drop" wasn't too bad, but the term "Cast Off" (moving the stock more to the right) and the term "Cast On" (moving the stock more to the left), was just too much for me at first. Still is little.
1. The pattern board is your friend, use the Dam thing!!!
2. The maximum range of a firearm and/or cartridge, is usually measured in miles, and means nothing.
2a. The effective range of a firearm and/or cartridge, is usually (the ability of the shooter) measured in yards, and means everything.