actually just replied to a similar post elsewhere...so i just copy/pasted & edited it a bit

you trim it to your template...so yes get rid of the bare "skin".
for the hair line you trim it all the way to the hairline WITHOUT snipping into the actual hair line (unless going for irregular, explained below). it is fine to snip away those few, sparse random hairs up front....
i advise doing it like this because i have found if the tiniest bit of bare piece skin is left it can be seen with indirect lighting, ie; light source coming from the side (NOT a TL piece but i suspect this is the case with all UTS). use a small sharp pair of pointy scissors.

also go very slow at the hair line. personally i try to do it with a slightly irregular edge. this means that unless you are extraordinarily meticulous you will snip some hairs and have to then pluck them out....not really a big deal though