To focus at infinity with an RB lens on a RZ you have to move it forward 13mm (if I remember correctly)
This means that the reverse would be true if you used an RZ lens on an RB body... to get focus at infinity you would have to shove yer RX lens into the RB body by the same amount ... cant be done
RZ lenses can be fired at ~1/400 by pushing in a little pin on the back face whilst also turning the cocking pins ... Its a good idea if they are going to be stored for long periods to do this - the RB doesn't have the mechanics to do this for you tho (if you were hoping to do some macro)