Hello Luc,
I've spoken to our Indoor AP product line manager and obtained a slide from his
presentation. Due to our patented BeamFlex in addition to MU-MIMO capabilities,
the horizontal or vertical orientation of the H510 on your wall will not impact coverage.
They are designed for single room coverage, so cannot guarentee what connection
rates will be in the adjacent room behind the AP, if you place them in the middle,
between two rooms.