Ricnunes, there is a difference between using missiles and using the gun. For the missiles you have two options always, use directly mando missiles (as the sidewinders of the AH1Z demo) or use BIS missiles which are substituted by mando ones at firing time (as the hellfires of the AH1Z demo). So, if using a BIS missile you are really firing the BIS weapon and BIS system computes correctly the number of weapons left (same for reloading). If you use directly mando missiles, mando missile system controls the number of weapons left, as well as reloading.
But for the gun the system is different, as Im not firing any BIS gun. You may just remove BIS gun weapon from AH1Z and then you will have only mando gun ammo count.
I know what you are talking about related to that manual guidance. This is already implemented inside mando missile HUD (visual launchers),
here you have an example. Probably I'll include that kind of manual guidance to the camera system.
Luke, read the instructions of MCC allow scripts, there you have detailed info about how to change filter colors, etc. You can try to attach as many guns as you want to any plane and using any ammo type (you may have a gun firing Su34s at 1000m/s).