couldnt this also be an indicator that the game is going to be online multiplayer co-op, since everyone would want to be mater chief.
This ISN'T a MMO will people just give it up that it is. Theres another halo game in devolpment maybe you'll get your precious MMO there!
To answer the original post, in the first skirmishes, well most of them up til reach, often 30-40 spartans would be involved in every battle, theres loads of war stories in the book about it.
There was about 120 to begin with (spartans), only about 70 survived the genetic enchancements or as the books like to call it 'augmentation'.