A while ago, my colleague Andrew did a research about that:
Actually, RTCM3 messages are lightweight, but it depends on how many and how often you send them. Hope it will help you with calculations!
We set 0.5Hz by default for RTCM3 messages. The base is stationary, so sending data every 2 seconds is enough for centimeter accuracy, but it produces a way less load on LoRa, for instance.
