So I just got 355k magic xp/h with C staff at Abyss creatures, compared to ~290k xp/h with Virtus wand and book.
I think it's also worth mentioning I had forgotten to activate momentum for the first 15 minutes of the C staff trip. Oh and I used significantly less runes.
Might try again tomorrow, perhaps I derped yesterday with the wand and book (it was late), but for some reason it felt faster with staff. Sometimes I'd 1-hit Aby creatures with it.