I used 4 1/2 back sinews to put two layers on my 60" ttt trade bow.
Leg tendons vary in length so much more than back tendons its hard to give a count. A little sinew can go a long ways if you comb it out good and get it nice and fluffy. If your strands are left bulkier you will cover much less limb and use much more sinew. I have notta clue on strings.
