I'm getting ready to attach my first thin skin unit and had questions about where the perimeter meets my natural hair. I was under the assumption that they should meet up perfectly, with no overlaps or gaps. In this video, there seems to be some overlap at about 1:20. What do you guys think?

http://www.youtube.com/watch?v=pSUrazo9u58

Yes if the unit comes back made exactly to the template size you should be able to attach it and have the edges line up perfectly with you natural hair. This makes for the best attachment, regardles of if it's skin or lace. If you get it right with skin though, you will have the best feeling bond and it will be undetectable to the touch. I am wearing a thin skin now and mine lines up perfectly. If it is slightly too small you can stretch it to fit too.

In the video you posted the stylist has done what most stylists do in this case: just slap it on his head any old way, nevermind if it lines up or not. You will see this alot on youtube. I have seen some guys overlap it more than an inch and in one case more than 3 inches!

Try to make sure it is a good fit and you can line it up and you will love how it looks and feels around the back an sides.

Gotcha. I ordered a stock unit with the new generation thin skin and it is crazy how real it looks against human skin. I'm really excited.

Hairenough, do you have to trim up any hair that still grows under the unit? I still have quite a bit of hair that naturally grows on my head, my crown is just FUBAR. So currently I have to shave the top of my head every week or so.

Yes you need to shave the part of the head that the unit will be bonded to if you want to get a good result.