OK, from what I read and understand, this is what it all means. If you thought it was "cluttered" before, look at it now ! LOL!
You have the bomb and rocket sites correct. The "ticks" on the site line...now connected with the circle... are your range markers. These are used to figure the "lead" on a plane. If your going to aim at a planes cockpit at 500 yards out you would place the cockpit of your target along the inner circle with the center of your site in a direct line of the enemy planes flight. Same goes for 1000 yards, but with the outer circle. They cut the circles down to "ticks" on the lines to remove some of the clutter.
The "inplane site line" is for when you are "saddled up" and following the same basic flight path as the enemy. Here you would use those "ticks", however should you be going for a plane that you are NOT in plane with.... a tracking shot, or deflection shot as its called.... you would use one of the "out of plane" site lines. ex: your flying strait a level...not good in a fight, but good for this example
.... the enemy is closing from you right...3 o'clock... and will pass strait in front of your going to your left...9 o'clock... Using the right center line you pull the trigger from the time he' crosses where the outside tick would be, to the time he crosses the inside tick... basically a quick burst. Thats what makes deflection shooting such an art, some have it some don't. With both planes closing at speed, you have to be able to to note the enemies distance, and the timing needed to hit the small window when he will be between those two points.
The yardages I use here, may very well be wrong. I never tested that site, but it give you an idea of whats what if ya got numbers to go by.