Which Perforce streams to use for UE5

Our studio would like to start experimenting with UE5 Early Access for our next title, we access the source through the Epic Perforce depot. We can see in P4 that there are a couple of streams … how does Epic use these streams and what is it recommended that licensees use? I would guess for us it’s either Release-5.0-EarlyAccess-1 stream or Release-5.0-M2 stream.

M2 is probably “milestone 2”? … how will that be used and when should we move to it and beyond?

Also, if there is any general advice on when is a good time to make the jump from 4.26 to UE5 it’s much appreciated.