Sounds like a big case ! Are you able to provide a photo of your scalp and donor region ?
Interesting that Eugenix & Westminster Medical Group recommended 3000 grafts, and the other clinics are pushing for 4000 - 5000 grafts.
You may wish to consider FUT & FUE to get the best yield if you have a limited donor region. FUE, FUT & SMP can work well also for large cases.