I think at the end of the day there is never going to be 1 set of rules that can govern all loot handling. It is bad enough the amount of loot drama before you even take multiboxing into consideration. Each boxer just needs to come to an agreement with the other members of the raid (Be it at the start of the pug, or with your guild leaders). Personally when I used to box with my guild I used to get full dkp on my main and half dkp for my alts. My alts all got geared eventually anyway, and more often than not I would pass items from my alts untill everyones mains had them. Everyone in the guild appreciated my contribution and that was enough for me. On a few rare occasions when I couldnt afford to pay repair/flask costs on all the alts the guild bank would pay.