honestly with the offset hatch it would work even with the breech partially or wholly inside the turret.. there would be room to load it, then the loader could duck down while firing.
the problem is the various fluff books put the crew at commander, gunner, loader, driver, and 2 sponson gunners. which suggests that it is a 3 man turret.. ouch.
the cutaway model looks ot have made the gunner sitting at a console in the hull, presumably controlling the turret remotely.