i'm not very experienced or anything but id say go with full bonding as its harder for four to sort out a hierarchy then it is for two, so i think they need to stay together and sort it out.
although my four didn't work out, they were going fine for quite a while but then one of the girls decided she didn't like one of the other girls and that made the third girl not like her and so on :lol: so they are two couple now but are happy to live right next to each other with just a pannel separating them :roll:
good luck! :wave: