[Mustang]

I didn't suggest two different fire control ratings, per se. I recommended that a tank's fire control be halved. As most modern tanks have an FC of about 40-50, it would make sense if their FC was reduced to 20-25 after a damaging hit.

And you don't have to integrate any more variants, as there is going to be enough shrapnel flying around no matter where the tank is hit, except maybe in the rear, to do plenty of damage. If you really want to be technical, you can set different FC knockout percentage values for every point (side hull, front turret, etc.) that the tank is hit.

And as for sensor-to-warhead target surface, these things are made out of glass. You can pierce or damage them beyond repair with a 9mm pistol. You don't need to worry about armor values.