Rather than make a true muslin, I picked up 2.4m of cotton voile for $14.00 to make a wearable muslin. To begin a took some measurements of the pattern, checking that the darts weren't too high, that the body length wasn't going to be short. I did length the arms by 2". I cut a size 8 and narrowed to a size 6 at the hip on the side seam.
I'm happily sewing along, following the instructions and feeling pretty pleased with myself and how fantastic the seam allowances looked on the inside with a french seam finish.