I run on two different servers right now, as a multiboxer, and here is my break down.

2 guild banks with at least one toon on each account with access.

on Gul'dan, Team one in El Diablo Team Two in Knights of the Griffon.

On Sen'Jin , I have one toon, with my team being leveled. Once there, The team will join the Guild.

I started off, not only for the challenge, But for when Raiders where few and far between, I was able fill in up to 6 spots if needed.

Stephen