This is an updated version of the reduced mana calc using the new formula (Aura Reservation * (1 + Efficiency)). I make no guarantees that any of this accurate, so don't flame ggg or anything. As more information comes out I'll update the calculator.
I tried to follow what they said the changes were here. Items and nodes with a (?) are ones I'm completely unsure about and don't know how it's going to work. GGG seems to have removed more/less multipliers. The UI for this calculator needs a bit more work now to be more clear on the numbers (stuff that says its x0% is actually using 100% increased efficiency, the ui was originally meant for displaying the reduced mana stuff, I'll update it in the coming days). Also the calculator may break the health numbers when linking around aura setups, I have to fix that too.
Link to the current 3.15 version of the calculator
Update: Got a confirmation from GGG what the aura math is and the calculations have been updated slightly (you shouldn't see a significant change in majority of cases, just ones where reduced efficiency was applied a la essence worm or something similar)
Last updated: Oct 10