after blowing my mind with another gigantic blast of gun-sight knowledge, I'm going to go play with it in offline...
Hell, I might make a video on it... "meh"
Try using this to build your N-3B for your B-25H....Kinda looks like a GV gunners optic dosen't it? Same principles apply to a 75mm whatever you have it mounted in. The one in the B-25H is the T13E1 / M5 Light Weight 75mm. Muzzle velocity: 619 m/s (2030 ft/s).
----CV - 230m long
~56Mil @ 4400 yards<----Maximum efective range for T13E1 / M5 Light Weight 75mm.
~63Mil @ 4000 yards
~72Mil @ 3500 yards
~83Mil @ 3000 yards
100Mil @ 2500 yards

All of this bacame simple because HiTech was kind enough to adjust his gunsight FOV coad so 1Mil=2Pixel in 512x512 mode. You just plug numbers into an angular mil formula and out comes width in Mil at any given distance. You determin the drop point for the 75mm by flying between 1000-2000 feet north with the offline target out. 4400 yards is about the maximum resonable range for the 75mm.
Then you take your generalised numbers for drop and distance and place Mil brackets on a test gunsight at about the drop point below center that you think the round will hit the deck or hull when the CV just fits between the brackets. Remember, the speed the CV travels is fast enough that past about 3k you need to lead it a bit or you will watch your 75mm round land spot on but in the middle of its wake.
Four or five hours later it works about 70% of the time.
This is still up to your skill to make it work. Before the real B25H received the AN/APG-13A gunsight radar, hits beyond 2000 yards were about 1 in 9. Hits 2000 and closer were about 1 in 4 even with the range dial on the N3 gunsight. Attacking shipping 2000 and closer was very dangerous for the B25H crews in the Pacific. The late war AN/APG-13A gunsight radar made it possible to hit ships at 4000 yards outside of most man aimed ack fire.
Bet most of you are just gonna try and covert this thing to a bitmap and tell me to "fudge off". Too bad. You learn alot more about flying and shooting the B-25's 75mm by following all of these directions to build your own from scratch. That picture isn't scaled to 1Mil=2pixel. It's from a (How To) I wrote for my "Pigs" back around August of this year.