We are migrating from 2 old 6509s to new 6509 hardware. The old and new devices are interconnected, 6509-1 has root, 6509-2 is standby, 6509-3 will be new root and 6509-4 new backup. Several access switches have dual uplinks to the 6509s, about a dozen different VLANs. The old devices have priority 8192 and 16384 respectively. Plan to set priority 2048 on 6509-3 and 4096 on 6509-4, put root guard on all their interfaces except interconnect, raise the standby priority on their configured vlan ints. Also turn on rspt on some access 4500s and the old 6509s. Old 6509s will need to stay on network for awhile. What is best sequence for least downtime?