The arrow proposition
vizwooden arrows vs modern is very hard to answer Timelord, but I will give it a bash. So if both arrows are the same "physical" size, and am I safe to assume that they are both shot from the same bow? then the answer would rely on which shaft had the greatest velocity, because if both shafts are the same the faster one would deliver more Ft/lbs of energy on target, but which one? to be honest I can't answer to my satisfaction, and rather than blag you I'll say so.
There are major problems with interpretations of historical weapons being based on modern assumptions of how they were used. I find this more prevalent on Youtube where everyone is an expert who can pick up a sword or bow. The light on the horizon is that we are now seeing a lot of experimental archaeologists carrying out such tests with materials as close to original as possible. This approach is the only method which can extract useful knowledge, the one of rigorous enquiry backed up by sound methodology. On youtube it would be some guy shooting through eight milk jugs with a modern longbow as a way to prove the "warbow" could kill a knight at 100yds
here's some of the links regarding conquistador accounts.
https://archive.org/stream/memoirsofconq...0/mode/2up
https://archive.org/details/anarrativeofthee34997gut
http://alkek.library.txstate.edu/swwc/cdv/book/1.html
This is more my area
http://www.academia.edu/2300543/Hunting_...plications