Demasoni and yellow lab tank?

i am an experienced african cichlid owner. i have a 55 gal tak and wnt to keep demaoni an labs. but i have never owned demasoni for fear that they will kill everything until there is only 1 fish left. has anyone have any advice for me. i have heard keeping a minimum of 9 is essential to dispurse aggression, and obviously the m/f ratio is important. any advice is appreaciated. i have a 55 gal tank with lots of rocks/hiding places for them.