A picture of the bow unstrung, in the same orientation as the strung bow, will show you where the set is happening. If one limb has more set than the other that limb is weaker than the other. Its not unusual for the upper limb to be bending a little more, due to the way most people draw the bow(more stress occurs in the lower limb, so it needs to be stronger, and not bend as much). It will also show if you are starting to get a hinge if the set occurs abruptly at one spot.