I think Ed's bow is pulling around 52 lb  I'm planing to make one of these bows but more of a native style in the 50 lb range  the way I understand it from Adam Karpowitz  book in a nut shell  if the bow is holding aggressive reflex & light mass it will out perform a wood/sinew bow being the composite material can be stressed to a higher degree I got a hold of a Gemsbok horn I plan on processing this winter I'm sure some body could explain that better but it would be interesting to see the numbers on a 45 lb composite bow I bet it could be built very light mass wise.