I think the current sight\reticle is a comprimise so you don't need a spotter to feed you range adjustments for the range wheel. I would still like a Spotter\Commander mode then to look around. The spotter had to be looking through something that gave him the ability to estimate range visa the relationship of some structure in his scope to the tank he was looking at. As I found offline our current reticle for the 17lb has relationships for range estimation based on the horizontal tick marks and an average 20ft long tank. Syncs up with the Firefly sight picture's range ladder.
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Until the beginning of 1942 British anti-tank gunnery used a 'false range', they aimed low and added a few hundred yards depending on the actual range. From the beginning of 1942 they adopted zeroing of anti-tank guns, usually using a tank sized target at 500 yard with the aim point being centre of mass. This meant the actual range could be set on the range drum, part of the drill for coming into action was to prepare a range card for recognisable objects in the zone of fire. They also issued simple tables for lead depending on range and speed and whether the target was a 'direct crosser' (45 - 90 degree approach angle) or 'diagonal crosser' (15 - 45 degrees). This was related the lead graticules ('lead units') in the anti-tank telescopes. Of course the time of flight of the shot from high velocity anti-tank guns at normal battle ranges was under 1 second, and a tank moving at about 15 mph covered about 7 yards in this time. A 'direct crosser' at 15 mph required a lead of 1 and a 'diagonal crosser' a half, the smallest lead order was a quarter.
