My thinking for the VIIb:
Rear torpedo room: 1 guy per watch should be enough. When in Battle Stations it would leave 3 guys in charge of a single torpedo tube. 3 slots deleted.
Engines rooms: 2 guys per watch makes 6 in total when in combat situation. Not unreasonable. Another 3 slots down.
Control room: must be really crowded when in combat stations

. 3 per turn seems more logical to me. 3 more slots that could be axed.
Also the Watch in the tower must be busy when in combat, with 4x3=12 guys looking for the enemy

. If we remove one set of 3, that would make a total 12 slots that could be removed.
56-12=44. We could add 1 or 2 guys to the damage control party. That would make it a total crew of 46. Plus the Commander/Player

, it's now quite close tothe 48 objective

.