All this number crunching is really neat and all.
However, in the maritime sector the crew sizing is done in a very different way.
The IMO rules (International Maritime Organization) are based on a worst case scenario:
Why? Because the bean counters will tell you that you can run a 150m plus ship with 4 or 5 crew (equivalent to a 2 person Mars crew).
But what happens when the shit hits the warp drive? Because, whatever probabilities tell you, it always will. Murphy ALWAYS wins.
IMO crew numbers are based on the minimal team size needed to save the ship/and or the crew. And thus you need 17 to 30 men (depending on ship type) on board.
But they don't just stand around waiting for a container to burn or the deck officers to get food poisoning from frozen lobster, they are used to do maintenance that avoid costly time in dry dock.
And in any case, the cost of the crew is but a rounding error of the cost of fuel and lubricants.
So for a trip to Mars, the same idea would be true. How many men do you need to do a 2 team emergency repair? 3, 4 even 5? Well that's your crew and they represent an insignificant amount of weight to put in orbit compared to the weight of the fuel to get them there.
So effort should be focused on getting fuel in space cheaper and using it more efficiently rather than cutting the crew leaving it unable to react to an emergency.
And if you got more crew hanging around, well, do MORE science.
Disclaimer - I sometimes brainstorm silly ideas for Copenhagen Suborbital.