In all reality we will probably never get archery right without anyone who has first hand experience in combat by archery (rare as hell nowdays) to tell us how penetrating arrows of different matirials are. The best way I can see to improve archery is ask a sport archer how far they can shoot and how often they can hit. The entire problem that I'm trying to bring to your attention is that we have no idea how accurate the archers of old were and how deadly the projectiles.
Why do you need combat for penetration data? Just ask (a) hunters and (b) hard core re-enactors.
While you're at it you can ask the same folks about accuracy and get data for at least some educated guesses.
It's not like archery and it's equipment and capabilities are some lost unknowable art. It's probably one of the easiest to research, because unlike say the martial use of swords it's NEVER gone out of style entirely, and the materials used didn't change until very very recently.