That’s very interesting David. So the drivers seat and visor were never lined up with the drivers hatch. By the time the F model came out, the front plate of the superstructure went straight across for the bow gunner and drivers positions as opposed to being offset on previous models but didn’t change the drivers hatch situation as I would have thought.
Getting back to the crew communication gear, there’s a short but good video on YouTube from War and History that explains the head sets and throat mics.