As far as the size of the 6-slot and 48-slot a Micro SIM is used. A Nano Sim is used for the 12-slot. Both a dynamic and static SIM card work. We suggest you get a SIM card connected to an IoT platform rather than a phone SIM card.
Sim card requirements:
kbps: 0.5kbps. Any of the standard 512kbps, 256kbps, or 128kbps will do.