Thanks for the screen caps Rabbit .. perhaps you could just put it in a separate thread and name it Trick r' Treat Sam caps and link to it here .. that'd be easier and more accessible for people looking for refs that won't necessarily come here!
Kylash .. what I did is I left about 1 1/2" extra all around when I skinned the second half .. I then cut an extra strip of burlap around 2" wide, then folded it 3 times over itself, which I then glued on the head directly on the middle vertical line going all the way around the head. I used the extra 1 1/2" left on the head to wrap around the strip than I sew over it.
Don't even try to fold extra material over the middle .. that material is so wavy from the shape that you won't be able to do this. Although my seam is thick, perhaps a 2 layers instead of 3 would have given a little better result. Still, I'm pretty happy with the final outcome ...
For the mouth, I had already glued everything on the head before doing the mouth. I suggest cutting the mouth directly on your sphere like I did (I ended up having no separation in the mouth so it's completely cut open on my current head. I then cut it up by segment with scisors .. not completely though .. I left some line that go through from upper lip to lower lip. I found doing this after everything else .. just before the stitching was pretty easy and I could always stand back, look at it, and add more where I felt I needed to... Very happy with the result .. I need to weather the whole head a little now ...
I'll have better pics of the final result soon...