I can't really answer your question specifically, but I can say that I have some of the Aeotec Multisensor 6 with ceiling mounts, and although it does make for a very neat aesthetic, it really does make them less useful, at least in my case. Their coverage is much smaller in that orientation. I guess that's to be expected, so if you're not really hoping for a wide coverage area, you should be fine.
I guess I didn't really think this through enough when I bought and installed these in my ceilings; I placed one in each bedroom, but since realized that it's very difficult to cover the whole room in this orientation. I also realized that using them for temperature sensors (the second reason for placing them in each room) doesn't work well, either. When the heating is on, the temperatures at the ceiling are so much higher than at floor/head height that the temperature readings are basically useless for any automation.