I had wanted try a couple of arrows the mesolithic style for a while. This is not any reproduction of scientific value, just a shot at that kind of arrow.
Finds of shafts from the mesolithic in bogs indicate they where long, around 40" to 44". I tested some shafts, came up with a spine of about 90 and 1000 grains mass for a 60-65 pound bow:
http://www.primitivearcher.com/smf/index.php/topic,51739.0.htmlRose shafts, dogwood foreshafts and nocks, sinew, pitch, jurassic chert and goose fletch, red ochre, charcoal and egg for the paint.
How do they fly? Low.
I made two blunt test arrows. It's really different to shoot, the first few went right into the ground halfway to the target. Shooting straight is real easy, the height is difficult to get right at first. But they hit home hard, I imagine they are excellent for big game.