sinew would work,, you just might have to extend the draw, ,but maybe not, worth a try,,you would definitely learn something and me too
ok I dont know how long the bow is, so I am just spit balling
but if you put sinew on ,,, it gonna go up in weight,,and will probably shoot the arrow harder,,
how effecient,, hmmmm well depends on if you get some reflex back in the bow,, maybe recurve the tips a bit,, etc,,,,
but I feel like getting to 170 is way doable,,
I dont know that much about maple,, but there is a nice shooting bow in there with sinew on it,,its easier I think than backing with wood,,,
but thats just me,, I think its a bit more forgiving,,
sometimes I have made sinew bows and they start to shoot really well before I draw them to half the bows length,, or when they are a bit to long,, but the chrono, tells me they are shooting nice,,I have even gone past the shorter draw to have the loss of reflex off set what gain I thought I was gonna get,,,, the sinew bows shoot so nice, I think you would enjoy it,,