M - for Barbarians.
L - for the rest.
Difficulty should be set to maximum, otherwise it's not interesting.
We need to decide on the ratio of race/difficulty/number of enemies. We could also add map size, but if everyone agrees with my "tribal brother" (judging by the nick and race :) ), then we can leave it as is. Personally, playing as Swamp on King and L is sketchy for me; otherwise, I am for it.