Hi, I'm on my 3rd JN pattern. Tried cutting all those little pieces and then tried to match them to the paper pieces pattern. Ppfff! My pieces were too small. I strip piece her quilts. I cut the strips about the size of the pattern. Sew them all and trim. It's massively easier. Unless you are a OCD perfectionist. I'm not. I'm a kinda sorta person.I
Try measuring the piece, adding the seam allowance and I add a bit just in case. Take into account the angle of the piece.
Like I said, I'm on my 3rd one of her quilts. They turn out stunning. Good luck.