So I've been Dual Boxing a Warrior / Priest. I've got them to 55 now and have a Orc Shammy I've gifted to the same level. I want to use the Shammy in end game content and get it there as quickly as possible. He's on the same account as the Priest, so if I do box, it will probably mean respec to resto and dual box with the Warrior.

Option A - Dual Box Warrior / Shaman from 60-80

Option B - Solo Shammy to 60-80