Add buff by Spellbook

Hi, a question concerning the "Add buff by spellbook" trick.
Can I add as many auras of the same type I want aslong as the spellbook they are in uses different order strings?

Yes, here is the AuraBuff function though i think u have it already.

Hmm ok, actually didnt have it before ;P
does it give an "duration" to the buff? didnt read it very clearly.

btw I see you remove the things from the unit when it dies, is that really necessary?