i agree, at 60 inch, thats kind of long for backing with sinew. your not going to gain much if anything. those pin knots look fine to me. you have enough off the sides of them . there shouldnt be any issues.if i was really worried about them and it was my bow, after i finished the bow id just sinew wrap the pin knot area . its osage its pretty strong, and a wrap with sinew over those pin knots wouldnt take away from the performance of the limb any and would insure those knots never could cause a problem. Tony