What was the upper limit on number of virtual monitors you could stream from a Mac when you were working on it? The demo videos only ever show one which doesn't

What was the upper limit on number of virtual monitors you could stream from a Mac when you were working on it? The demo videos only ever show one which doesn't seem all that useful. Optimally you'd be able to just drag the actual MacOS windows out into space and the cursor would just hop to them when you look at them.