Are we limited by number of our grafts

[Dav7]

I'm just wondering if we are pretty much 100% limited in what we can do with our hairlines based on the amount of grafts in the scalp - say 6,000 per average person, or a bit more or a bit less? Or is it the case that nowadays, even if somebody had used up a lot of their scalp grafts, they could still get a transplant from body hair? Or are we still 100% limited in overall terms to what our scalp can produce?

Also, will we still need a lot of grafts in our head when histogen is released, or will grafts be irrelevant at this stage, so that whether you have 7000 grafts in your scalp, or 0 grafts, it would be irrelevant? Or will graphs still count, both literally and metaphorically?