This is mine. I have a VERY hard time aiming. Old guy, old eyes and what Morfiend use to call "Old man syndrome" where the closer you get to your shot the more you shake the stick around due to excitement.
This is the site I made. The basic version all are the same with the 2 dots, lines, and circle, but they are modified for each gun platform. The center pip is the guns, the lower pip is rockets, the lines are to adjust my wings in crossing shots and the circle is the wingspan of most fighters at 250 or 300.
The modification I do is to adjust the center pip and lines lower for guns that have more drop. The 50s center is just a bit lower than center, the german 20s are lower than the 50s and so on. With this site I can put the dot ON the target in a trailing run, fire a burst and roll out and be sure of hits. No thoughts on "how much bullet drop" to add into the shot.
Before I used this site I couldnt keep a 2% hit percentage, now I'm in the 5% range most of the time.