I wouldn't say you messed up. These backed bows are kind of a different animal to tiller. There is a real tendency to have it bending too much near the fades. It really helps if you taper the belly slat and the bamboo backing prior to glueup. You get a lot smoother R/D profile this way too, with less cranking on clamps. And a lot of people put in a power lam either between backing and belly, or between belly and handle piece. I usually put a power lam between belly and handle piece, its easier to do. The power lam bolsters that inner limb and makes it easier to avoid the hinge near the handle.
You might be surprised to find how little amount of scraping it might take to round up that left limb. Once you get close, it gets pretty touchy. Thats good because you won't lose a bunch of weight making the correction.
One more thing, I recommend you photo yourself drawing the bow as a final step in tillering. A lot of times the tiller will look quite a bit different from the tiller tree, when it is in your hand and being drawn.
