Hi,
the horizontal convergence in general was adjusted to provide a most wide range of good hitprobability.
Many people forget that the bullet start good below the gunsight. If the bullet stream got adjusted to cross the view-line at 200m, the bullets will move above the view-line and cross it again at MAYBE 500m(depending to the ballistics). So actually there are two points of horizontal convergence and i doubt the bullets move so much above the view-line to miss the target at all.
The main problem with the MK108 and other slow muzzvel guns appear while shooting with a lead and with a banked plane.
Even on the ground(no additional drag due to the plane airspeed) the MK108 bullet need more than 1 sec to reach 500m, while the target move more than 140m/sec (500km/h, i guess that was roundabout the speed u had after u got out of the blackout).
So even on 200m the target move more than 55m/sec.
If your plane is banked, your hitpoint move sideward, cause the upward adjustment now is a sideward adjustment, while the bullets still fall downward.
A convergence of 650 should be the best for the center mounted guns while shooting to strait flying targets, cause then the highest point of the bullet is at 650m, while the lowest point still is inside the targets(the distance between gunsight and cannon is rather smal in the 109).
As result you also have the smalest influence while shooting with a banked plane and you still can hit on 800yard
On the other side you will need more lead while a turnfight, to hit the target. If you adjust the convergence to 150(yard) the bullet will be above the viewline at 200yard and will fall down below it at maybe 600m.
As result you should have a good convergence on common shooting distance and you dont need as much lead while a turnfight shot, but you need to beaware of the moving hitpoint while banking the plane and that its almost impossible to hit above 600yard.
Greetings,
Knegel