Hi SS,
As you have already metioned that you have defined descriptive characteristics for customer, you will have to map the descriptive characteristic with field cataloge for customer in the customizing.
In CTM you can use the field catalogue for sorting the forecast. The orders will be sorted based on individual customers.
If you need to sort the customers in a pre-defined order, you can also define special sorting for the field catalogue in customizing.
It is always better to define clusters for different set of customers and define characterisitcs on cluster. This will help in reducing the maintenance in customizing in case of large no. of customers.
Let me know whether this was usefull.
Regards
Ajith Kamal TN