Surprisingly, Ball Turret Gunners had one of the best survival rates of all positions. It was a small cramped position, but it was also a small area to hit, and not a primary aiming point for fighters.
If I was going to make a Nav position, I'd just make the 5 feet area where the table is, and the fuselage side to just above the windows. See diagram below. I'd make the table, seat, fuz side and then probably work towards the lamp and oxygen gauges etc at that position. But it would still need to be easily transportable, together with the other stuff I need to carry about. It may be impractical, but it's just throughts buzzing around my head at present.
So to go back on topic, what other toys did people get???
Steve