Frank,
I just glanced at that bow. Very cool design, not what I want to do, but nice.
This suddenly reminds me of the burial mounds near where I was stationed, south of Augsburg. It was a huge defeat by the Magyars by German forces led by a Bishop Otto. The West Woods had hundreds of burial mounds, some many feet tall. I wonder how many ancient composite bows were directly under my feet when I went and visited the site? I never brought a shovel, as tempting as that was!
Lennie, my thoughts are to make the core and other layers around 3/16", but maybe a bit thicker would do. And I do want to avoid messing with the horn too much if possible, but light work would not hurt, as you pointed out.