When I get my raspberry pi to start testing with my 8300 what size card should I get? Also what OS should I load?

I've set up IPSC systems before with a master and peer. What I'm not sure of is the bridge actually the master and the repeaters peers? I don't think there is anywhere in the CPS to designate a bridge.

N1XBM
Apparare Scientor
Paratus Communicare
Allstar Node # 27086, 41540, 41812, 42086