This mount is very flexible, but one limitation is that the two centres (=VESA holders) of the Moitore are at the same height from the table. And as already written by Patrick, the height adjustment is not hydraulically supported, so you should adjust the height once and then leave it.

Yes, both are possible. I have 2x 27'' monitors. But then it gets a bit more difficult. These arms are not hydraulic! That's why it's a bit awkward if you have to adjust the height more often.