Staring out, I'd recommend Keyclone (www.solidice.com/keyclone). With only two, its easiest to go with simple macro's.

Could use (Toon A = master; Toon B = slave).

On master, place spells on wherever you like for the action bar.
On the slave, make macro's which are very similar.

Slave macro's:

#show
/assist Toon A
/cast Shadow Bolt

#show
/assist Toon A
/castsequence reset=target Immolate, Curse of Agony, Corruption

#show
/assist Toon A
/cast [nochanneling] Drain Life

Some things like Lifetap or Hellfire, you won't need to assist, since targeting isn't important. Just put them on the same hotkey.