Best spot is to have them on the balcony on the lower left corner so they can't spread around at all. Gripp had really the perfect map on his Blizzy, IIRC he used it also for testing purposes (only) with other chars. I also have two Blizzard Sorcs and tried for countless hours but never got something like that. But it doesn't make too much of a difference if you have them tightly packed somewhere else on the balcony IMO. Just a matter of figuring out where to teleport so that the AI doesn't think of spreading out. I believe in the rune finding guide there are some guidelines regarding the map also.