Prior to knowing what is the number of grafts I would do, I would have to know 1) what is your donor density and the health of your donor area by trichoscopy, 2) what is your hair thickness of hairs in the donor area (fine, medium or coarse measures 30, 50, 70+ microns in thickness respectively). The thicker the hair, the less the grafts needed. Your hair loss pattern is unusual, but that entire central area runs the risk of loss unless you take some drug like finasteride to hold on to that hair. Before you jump into a hair transplant, I hope you share you age with me.