Keep in mind long range, and high zoom are apples and oranges. High zoom kills internal travel (exceptions being high end 34mm scopes), and internal travel is whats needed for long range. High zoom is for benchrest.
Put me firmly in the camp of fixed power, BDC for distance. (Man-sized, field shooting.) The last thing I want to do when taking a shot that matters is math.
AR style rifle - something in the 3.5 - 4 range. For a more precise bolt rig, go with a 10.
...and as everyone's said. Call Alan. He'll hook you up with exactly what you're looking for.