I already have a mod going as well that makes the changes to the zoom and elevation parameters (cameras.dat).
Also have an altered periscope mask ready with the graticules drawn on it. At the standard 1.5x zoom, the hardcoded ones aren't visible to begin with, problem is the markings are a direct copy.
Actually, don't know if it's bad, haven't tested yet. Maybe the original markings make sense once the base zoom is changed to 1.5x.
Here's the .dds, dont know if will be any good to anyone;
http://www.filefront.com/15875575/Pe..._1024_SH5.dds/