Niose 2

I have some overview type questions.

how many nios 2 processors can be put onto a cyclone 2 device?(best/worst case senario)

how many nios 2 processors can be put onto a cyclone 3 device?(best/worst case senario)

How hard is it to share memory between them?

I know there are many different possibilities considering different processor and chip configs, I was just looking for a general answer. I specific is desired I have a de70 device. Perhaps how many can fit on it?