Just something to pass along to you guys-you seem to be rediscovering Asian pointing, especially such as Turkish arrows had. Many had internal tangs of 6" or more, the tang could be cut to tune an arrow, and with a horn cushion behind the point and a bone collar on the cane behind it, those arrows have been proven to kill a cinder block. There's lots of experimentation that's been done, a lookup of the free e-book Saracen Archery will tell you lots about how their integral head/footing worked.
I shoot whenever I can with heads like that, and I'm finally dropping the coin to try and make them, but mine won't probably be ready for a long time. My point is, with their tuning and durability advantages, I prefer that type of point over anything else. If it worked for fully armored humans, it might help you guys, too.