Basically, I'm going gestalt, 11 levels, and I want to make an archivist with circle magic. Halruuan elder and red wizard won't work, as the other side of gestalt is already in use for factotum/warblade levels. The main problem is, how to classify for Hathran at level 6(Entering the class at level 7) with an archivist? It requires 4th level spellcasting.
I could afford to lose a couple levels on the other side of gestalt to meet this requirement, if needed.
So, Archivist 6/Hathran 5 at least, but if Archivist 5/Hathran 5 is possible, it's even better for simulacrum tricks.