I personally kill the 6 brothers, then 5 monsters to get a killcount of 11. Any higher than 11 gives you a chance of getting a D Med, which is kind of a slap in the face. (Which I believe most people want to avoid?) I don't think brothers count as KC anymore. I get 3 KC and that gives me runes back, also wear a ring of wealth for additional prayer pots from the chest - they usually lengthen my run by about 3 chests. Anything above 20 KC is pointless.