Changing your convergence will not change your aim point. Setting convergence to 650 and your aim point is at 250 makes things a bit complicated.
When you T&B, you don't do much shooting with our aircraft level. If you lower your aim point for bullet drop, the only time your sights will be correct is when you are flying straight and level. I think you are better off leaving your aim point and aim above the target.
I think shooting at too great of distance is a mistake when you are T&Bing. When you are turing with an enemy, you want to position yourself behind him to set up a tracking shot. You do this by lagging, or pointing your sight behind the target. If you go for the shot too soon, you are leading your target. This will make you loose your angles (position) or you will overshoot (pass in front of the enemy).
The next time you run out of ammo, keep chasing the enemy and you will see what I mean. You will be set up for the best shot and wish you had one more burst of ammo
The reason for this is because when you are out of ammo, you quit trying to lead the target, and you start following.
Just one dweebs opinion
Good luck!
Gunner <CAF>
GunrCAF