Thanks. I shortened it last night and re-tillered it. It's still only 63 lbs! I'll have to call this one another failure, but a good learning experience. I'm well impressed with elm though.
Jeremy, I tend to keep the outer limbs quite chunky until late, as I can have a deep nock to hold the string well during tillering. I'll try some horn nocks (my first) just for practice.
Marc, yes heat treating sounds a good idea. The weaker limb is still a bit weak after shortening it. Could I heat treat only one limb? And could I do it over a gas ring in the kitchen? (no heat gun as yet)