It's fine if you keep Greater Auramancy in the side because you only are really gonna use it against non linear decks. That way you can side out a Demonic Pact that you use on decks without hate for a Greater Auramancy.

Well i won't run Demonic Pact with this build anyway, I would re-arrange the whole deck considering even more black enchantments, it was just an idea I might toy around with once I have the patience or motivation to do so ._.

Oh I almost forgot- the reason to main Greater Auramancy is given with cards like Path to Exile beeing run- exile hits the deck hard, cause exiled cards can't be reanimated using the Starfield of Nyx, so if an opponent exiles lets say Sigil of the Empty Throne (once it is a creature), it can be pretty bothersome, that's why I considered the advice to run it main, I wasn't able to play Magic for a month now though and I know that a new Eldrazi deck is on the run, I might change cards once I am able to comprehend new matchups

What do you think of Privileged Position instead of Greater Auramancy? Would it still be too slow even considering your significant ramp package? If you can work it, it also protects your lands, Birds of Paradise, and Herald of the Pantheons and gives you more flexibility with cards you might want to include in the future that want you to target your own permanents.