Since you had mentioned the artillery Luger rear sight, I thought I'd post this alternative to that sight...
It's from a Martini. The star in
red is above the Luger artillery rear sight for comparison; all other pics are the Martini, leaf folded & extended. (The F indicates Front). The base is ramped and is graduated 50, 100, and 200 meters. The leaf is graduated 3, 4, 5, and 6 hundred meters. The elevator has one V-notch, the leaf has another.
It's designed to be soldered onto the barrel, but I am confident that it can be milled/dovetailed to fit the artillery Luger barrel/sight base.
The ramp is straight and the graduations staggered, the opposite of the Luger. After you hit 200 with the ramp, you would flip up the leaf and continue to 600.
Interesting.