Thanks to all for the wonderful comments!!
@ Ohma & snag: Guys, please forgive the carbons. I normally shoot 50-65# and all my bamboo arrows are "spined" in that range. I keep the lighter spined carbons, and the poplar that are also in the group pic, on hand mostly to shoot in the lighter bows I make for other people because they are cheap.
I personally think that natural shafts shoot better off longbows regardless of whether they are modern (insert dreaded "Fibe..." word here) or primitive due to superior bending during archer's paradox for the off center string line. I haven't had a reason to invest in POC or Bamboo at the lighter spine weights for myself...until now. If it makes you guys feel better I did order a dozen bamboo arrows today.
Hopefully you two, and anyone else on the forum, weren't too offended by the presence of the carbon on this otherwise primitive site. If so, then I apologize. - Mike