Yes the let off % will tell you how much weight you will be holding at full draw. The higher the let off the less weight you will be holding. I have never heard of a longer bow being easier to draw based on the length alone. In fact I think that it would be opposite. The closer you pull at a 90* angle the easier it should be to draw. I think any way. The biggest thing is the cam design. Some are very hard, like a redline cam, and some, like a round wheel are very soft. You might want to drop your weight down to 45# if you can and work up from there.