sinew must be prepared before using on composite bows,, i have used leg and back sinew, the leg sinew will always be softer after preping, although the leg tendons will work , it is much more coarse, and takes more time and a little different technique for it to end up the same way after application,, as far as laying down a whole sheet of backstrap sinew,it just wont work,first you will have to remove the mylar sheathing from the outside of the sinew,, this can only be done after the sinew has dried( the thin see through membrane you see while your working the sinew down to size),even if you could get all the membrane off the sinew without disrupting the sinew strand, when you dipped the sinew in your glue it would only be on each side of the piece,and would not be sufficient to hold everything together,, this is why you have to break the sinew down,so when it is dipped in glue ,everything will bond and become one whole homogenous entity, Adam Karpowicz book Ottoman Turkish bows is a must read,, also he can explain this in a more sientifical manner,, fred you did ask a legitimate question hope this will shed some light,,,,,,,,,,,, james