I have 2 two-switch 3750 stacks, which i will be combining into one 4 switch stack. All 4 are running the same IOS, and presently each stack is has priority 15 and 1, respecitvely. One master will continue to be 15, and the others will be slaves. Looking for best practices as to how to do this. Should I demote the master of stack #2 before joining both to stack #1?