well you learned an important lesson: by the time the lumps show your E has been elevated for a while, which means the harder it'll be to bring it back down.
It becomes even more complicated because arimidex lowers the plasma concentrations of nolva.
So I'd actually use aromasin, personally. If it were me, I'd go:
-25mg aromasin daily
-40mg of nolva
Once the lumps are gone continue on 20mg of nolva for the rest of the cycle, and lower the aromasin dose to whatever you need to have a normal E range.