Me too.
At 100 grafts per sq cm- and from what I tested on myself- thats a very high number of grafts.
So, at 100 grafts per sq cm a 2 cm wide strip and a 25 cm long strip can no way give intact 6000 grafts.
Your head does not look too large to me.
I hope there was no sub follicular grafting involved. That would be a shame, though it will explain the numbers.