I use the SanDisk Extreme Pro 64GB UHS-I/U3 Micro SDXC, which is a lttle bit faster. I buy memory cards for the speed I can copy off them, rather than the write speed (as long as it is fast enough for the device it is used in), because of the time it takes to back up multiple cards.
But it makes little difference in the MPW which only achieves 10 to 12 MB/s copy speed anyway, because the internal SD Card Reader seems to be connected to the main board via USB2.0 or equivalent. No USB3.0 speed there.
Still, it is fast enough for backing up video each night on a trip away. I just gave up after a couple of days as I noted that some files weren’t copied across, and I had an alternate backup facility in the group I was travelling with. We backed up about 26 video cameras, mostly GoPros, every night to five 2TB USB3.0 drives via a laptop with USB3.0 ports, and a nine port USB3.0 hub. It took hours every night. But then we had a support vehicle to carry all the extra stuff. We were all on motorcycles.
Many “regular 32G class 10” cards can’t even really achieve the 10MB/s sustained write speed they are supposed to, and their read speeds, the important thing here, aren’t much better.
You would think all adapters, being just a wiring connection, would all work. But I have heard other people say that a particular adapter doesn’t work with faster cards. I now use the adapters that came with the SanDisk Extreme Pro cards, since they should be the best quality and handle any speed cards I have now.
Anyway, learn the My Cloud App well. Watch ALL the training videos as there are some tips and tricks in them that are not really covered in the manuals. Of course the interface has changed a little since the videos were made, but they give you the idea.
I hope it all goes well for you and you get great footage!