I had a similar problem with a short 50 inch ashe juniper bow I just completed. I'm not a big fan of ashe juniper but I have three staves and decided to try making one into a bow. Looks very similar to the one pictured which, by the way, looks very good although I agree with others who think the right limb is a bit stiff. Ashe juniper is tricky in tillering because it's so soft, i.e., you can overdo things if not careful. Anyway, it was bending a lot through the handle and needed more bend in the limbs. Stubborn and persistent (I had already backed the bow with Irish linen twine) I went back to my cabinet scraper and started the methodical shaving of paper thin strips, watching the tiller and pull weight with caution and care, and finally, I got a bow that pulls 49 pounds at 22 inches which works for my Indian stance, hunched over shooting style: Great for hunting in the South Texas Brushlands.
NOTE: Short bows have their place. When hunting in nearly impenetrable brushland anything longer than 55 inches becomes ungainly and awkward. Shots are usually no more than about 20-30 feet.