Have a look on Thread 798-1185986
For time slot, dependig how many CPUs (2 redundant or number of SSC..) how many SS, how many MC.
As example, i had 1 CS + 2 SSC + 2 SS + 1 MC and need about 3 hours. But you need to have a very good understanding of how system is working. You can also add time to prevent any surprised from the system... and it happens ... ;-)