I have two shadow priests I'm leveling up together (currently level 22). The combination is wicked nasty, but I'm looking for advice from more experienced botters concerning specs.

Most grinding builds for shadow priests are built around mana efficiency and wands, using spirit tap to restore mana very quickly after a fight. Unfortunately, this requires that a character gets the killing blow, effectively cutting its efficiency in half when using two boxes.

Likewise, I kill so fast that most things die rather quickly, making wand spec fairly useless, and improved shadow word: pain even moreso, as nothing lasts long enough to get more than 3-4 ticks of SW:P normally.

Anyone have some thoughts on a 2-box friendly setup for dual shadow priests? I'm kinda stumped.