It doesnt matter, the tuners are floating tuners, so whichever order you turn on the receivers, is the order to which they take the tuners. Recordings will take priority over live TV and PTAT takes priority over all Else
Yes, good that we needn't concern ourselves with which tuner. The Hopper handles it all automatically and we can easily see what's what at the TV Activity screen, which I use A LOT to get an understanding of what's going on and for choosing to JOIN any tuner as a way of not losing what's in the buffer when I change rooms.