I think the hairs get their full normal look in the 8 -12 month range. That is a bit of a guess, but by then the hairs have been in for a while and have a chance to mature, which should address the wispy look. Also, I am not sure on the hair diameter thing, but it does make sense if each hair is twice as wide, overall, it should have a denser look. I think that is why you see improvements in the later stages, since at that point you really aren't growing new hairs. I agree that Dr. Keller did an awesome job on your HT.....just a fantastic result.