Forget the # of players thing in the equation because it messes up the formula. An M=4 would be a 1200 stack at 100/200 blinds w/ no antes at a full table. What he's trying to say about the number of players is, as the number of players decreases your effective M decreases and thus need to make another calculation. Assume a full table is 10 handed so if your M = 4 at a 6 handed table your true M = 4(.6) = 2.4 (the lower your M the more chances you need to take in getting chips). I'm saying the exact same thing as he is above except factor in the number of players after you calculate your M using M= chip stack / blinds + antes