Steve I have had similar thoughts about the light weight of bone points, more specifically in relationship to how a lighter point effects the spine and therefor flight of an arrow shaft. As an honesty disclaimer Last year was my 2nd year building primitive arrows, I have learned a lot but have not put one through a deer. Last year I tuned shafts with steel points and once I knew what weight that specific red osier, wild rose, or bamboo shafting liked for good flight I mounted a much lighter bone point, weighed that specific point, determined the difference from the steel point in flew well with and added wire to create the same tip weight with bone and therefor the same flight characteristics. I could not fit enough wire in a pith or center of shafting or I would have put it there.
Just an idea to share. You will see in photos this does increase shafting diameter and possibly effect penetration? It was also an error I realized for me not to notch and sinew the bone heads in photos to the shafting. they seemed solid with pitch alone but didn't hold up to use as well as I thought they would.