The default baud rate has little to do with anything. Sending 8,000,000 bytes of data, per second, is unrealistic, no matter what the baud rate. How much data comes in at that baud rate? How much of that data do you want to send over the radio?
I absolutely do not get that remark. If the GPS sends RTCM messages via 9600baud serial connection, 9600 bit/s is an upper boundary for the data rate I am facing. The actual data rate will not be below that by orders of magnitude. The datasheet suggests that I will be facing around 1-2kbit/s RTCM messages. I did think about getting the data down by parsing the serial commands and converting them to bit representations, but I figured that would create some headroom, not go into the initial evaluation.
How exactly it will look, I can only tell after the evaluation boards arrive.
How much data loss can you afford? How much of the acknowledgement/re-transmission process do you want to handle, vs. having the radio's microcontroller handle that?
As far as I understand the procedure, it is probably better to have as little initial data loss as possible and then ignore any losses that still occur in favor of transmitting more recent data.