Not sure if you are still looking at an answer to this problem. First you need to have all the inputs right . The following are the inputs you would need
1. Average daily Forecasted Call Volume
2. Average Handle time for the calls (Talk Time+After Call Work time)
3. How many hours is your center open?
4. What kind of Schedule adherence you plan to achieve?
5. What kind of Shrinkage (time for breaks etc) you want to use?
6. What kind of Service level you want to achive?
Once you have all these major assumptions you can use an Erlang-C model and calculate the Staffing and see if the Occupancy level is acceptable to you
Feel free to ask me any further questions