I never use formations in arena, i tend to circle around to try and spread the magma totems a little making it tougher for a rogue to get close and get a sap off. The only formation i do have is the cross but thats only ever used in AV in the bottle necks. The 5th player i have was a dedicated healer. The only reason i used it the other day was because i knew you were a boxer and wouldnt move away from your totems, so i did the same xD