My experience has been that the skin materials just don't cut it for full caps.

Now granted, i have not tried the latest, thinnest skin, but the bases I have had just won't work for a few different reasons.

First reason is that the thicker skins all have an abrupt hairline all the way around the piece. Now I have had a poly unit in the past where the skin extended beyond the hairline and even had a little lace injected that gave a decent transition, but the skin perimeter units lately are simply skin with hair injected right up to the edge. No way to expose hairline, and you'll be busted in half a second if someone touches it.

I might get brave and do a unit with a skin perimeter (if they can give it a proper edge), as I like to have something that I can throw on and off during the week in between lace piece attachments, but for now I'm simply sticking to all lace.

And as far as length goes....my current unit is as short as 1/8" (maybe even a little less) directly above my ears. I wouldn't buzz the whole piece down that short, but it looks good, believe it or not. The problem with going so short is that as the unit thins you are going to be able to see thin patches much sooner than if the hair was a little longer.