This is my math: 6000 donor follicles available. Average head has 100000 hairs. Can lose 50% of hair density before it’s visible. Say a norwood 6 loses 60% of their hair (40% left on sides) that’s 60000 hairs. Need 30000 hairs replaced to reach 50% density and look like a full head. Average graft 2 hairs. 15000 grafts = 30000 hairs would look like a full head. Could sides be over harvested from 6000 to 10000 to replace 20000 hairs? 2/3 of full apperance. Sides clipped to no1 with SMP to cover overharvest?
Answer: ?Your math is partly right. The donor area is always determined on the Class 7 scale not the Class 6 scale, which essentially reduces the donor area to about 20,000 hairs or 10,000 grafts, which can be harvested at say 60% assuming that you have an average donor density. Graft numbers are adjusted according to hair weight (coarse vs fine), color and contract between hair and scalp and hair character. The artistic judgment of the surgeon manages the multi-variant analysis as everything is not by the numbers alone.