6 is Slannesh, 7 is Nurgle, 8 is Khorne, 9 is Tzeentch
I think you should go for 10 man squads in rhinos, as a couple of pie plates = spalt
I think you need a termicide squad or some oblits to make it viable, just my 2 pence
BTW not all world eaters are bereskers, just the majority
, some still use bolters.