I set my convergence at 300. I try not to shoot until the range drops to 200. How many airplane lengths do I lead 90 degrees off, 45 degrees off, and strait 6 shot? Were talking horizontal and vertical lead here. What are your suggestions?
I need a darn light on the dashboard that flashes "SHOOT NOW !"
It's going to sound like a smart-azz comment, but here it is...
It all depends!
I don't think there's any real point in giving you any real numbers when it comes to that, because it depends on too many factors, and too much judgement, at a time when you won't likely be able to run all the factors through your mind, make good judgements, recall the correct number/distance, and then apply that number/distance to your shot.
As an example, I've figured out how much to lead a running deer in order to hit it with my muzzleloading rifle. I know that if it's running broadside at 100 yards at full speed, I need to lead it by "x" feet to hit it in the ribcage.
That may be interesting, but how practical is it in the field? Not all that practical, unfortunately, because there are too many variables in reality, and I don't have time to think about them in the brief opportunity I have to get a shot off.
Is the deer really 100 yards out? Is it really running full speed? Is it really running broadside, or is it quartering a bit? Is full speed over a hayfield the same speed as full speed through soy beans? Is that lead amount based on me swinging the rifle, or holding a set point in front of the deer? Am I swinging with the deer, or did I start swinging from behind the deer and I'm pulling the muzzle out front?
Is it still running full speed after I've made those calculations/judgements? Still broadside? What was that number again? And was that "x" number of feet in front of the deers nose, chest, or ribs?
Good thing I'm not excited, nervous, cold, or need to take a leak! Good thing it's not a monster buck, just to distract me! Good thing I haven't missed the last 3 deer I've shot at, to shake my confidence! Or hit the last three, which could make me over-confident.
Now, that's standing with a rifle. That doesn't include the complexities of an aircraft... I'm I closing on him? Or is he pulling away? Am I banked? Pulling G's? Pointed upwards, downwards, or level?? Are you holding a sustained lead? Or firing a snapshot as he crosses? Is his apparent crossing speed due to his flight path, or mine instead?