Jesse, Even if you hit 50# and have a hint of reflex it should shoot plenty fast..Here's a couple tricks which will help you get more stability and poundage.
Actually the taper from the handle out is fine. The last 8" or from the center of the curves needs to taper more. Also overlays which make the tip section taller than wide will amplify the instability. And usually on bows like these I trim the bamboo at an angle where the overlay goes so the knot or loop is flush with the back of the bamboo or very close.
So by shortening your bow to 62-64" will locate the limb curve farther out, and combined with sharpening the taper, and changing the overlay will make this bow stable. It might make the poundage you want as well.. Shortening will allow you to also remove a small amount of belly wood which can also change the limb profile in your favor by getting it a little wider relative to the depth. On reflexed bows like yours subtle changes can make a large improvement.
Also if the limbs wants to go one way, the nock placement can be adjusted by filing in one side to bring the string towards the other side.
sometimes when I string up a reflexed slender ipe bow the limbs may wander to one side, and I use these tricks to straighten it.
Rich