that's good, taking your time is how most of us have to do it. Besides, you can catch mistakes if you take it slow, if you don't there's a chance that you will slip up and wind up with a less decent bow. I think your doing fine for now, but like everybody said outer limbs aren't bending really. And yes, a tillering tree is a massive help in my opinion, its nice to step back and see whats going on without looking in a mirror or something and trying to check it.