If you use the Switch Library feature, you actually have to create a separate library backup file per library. There isn't currently an option to backup all libraries at once, although this is something I can look into supporting in the future. If you restore a library backup, it will restore into whatever the currently selected library is, so you want to make sure to uncheck the option to restore settings when restoring to each individual library.
You can't currently sync multiple clients to one server. There is only support for synchronizing one device at a time. Having said that, you can technically sync multiple devices to a cloud folder at the same time, but if you do this, I would highly recommend using a one-way sync to only pull down changes from the folder, as you wouldn't want to try to modify the folder while tablets are actively synchronizing to it.
I'm the developer of MobileSheetsPro and Zubersoft is just a one-man team - myself
Mike
You can't currently sync multiple clients to one server. There is only support for synchronizing one device at a time. Having said that, you can technically sync multiple devices to a cloud folder at the same time, but if you do this, I would highly recommend using a one-way sync to only pull down changes from the folder, as you wouldn't want to try to modify the folder while tablets are actively synchronizing to it.
I'm the developer of MobileSheetsPro and Zubersoft is just a one-man team - myself
Mike