As the title implies, I'm planning to start 5boxing sometimes soon, working on setting up stuff and all, but one thing that I'm wondering is, what do people do for 1-15 level ranges(15 being the point when you can start running RFC efficiently from what I understood). I'm not doing a 5shaman team, but a 5different class team(protadin holypriest mage lock elemsham), but training and such aren't a big issue since I'll be using the new blizzard offer which lets you summon people around as you please.

I'm wondering if I should do 1-15 in a group of 2 then a group of 3 seperately, doing quests, or if I group all 5 in the same place and just grind away on random mobs, or do quests with them. What do you think would be the most efficient? I was thinking of just grinding since questing at these levels with so many chars might prove annoying(can't really afford to skip collection quests), but even with triple xp from the blizzard offer, grinding non elites doesn't seem to be crazy xp at all.

If anyone with the same kind of setup(or just 5shaman stuff) can comment, thanks.