Lol, my guess for working limb length was in the ballpark at least. So your ratio is 1.71 not the 1.6 something I guessed at earlier.
So, take the width of your bamboo yew bow, add 1/4 ( or 3/8 , your call i dont know yew ) to it, and multiply that by yout 1.71 ratio.
Do that every two inches of the bows working limb, starting at the fades working outward until you hit the stiff part on your new bow.
With the difference in backing material, for the tension side of things, im not certain how well your backing strip matches yews compression abilities. If yew wins out, you may consider rounding the belly to give the back more surface area than the belly. A reverse trap really. How much do you know about your combination of wood there?