Given that your tiller is off on both limbs in different spots, both limbs will need scraping to get them symmetrical. Honestly, I would leave it be and shoot as is, but boy are those limbs bending!
And to answer your question, If you were to scrape the limb to match, I bet you would loose 7 lbs. Also, in doing so, you would turn the best limb you got to match the worse looking one. If you must do something, take the bamboo back off, heat treat the weaker limb to make it stronger, then re tiller, and after the tiller is good, glue on the backing. You wont loose any weight that way.