|I just bought (and reviewed) a flexible curve. I immediately grabbed the two people I sew for and used the curve to determine their front and back crotch curves. Flexible Curve Review
As soon as I was done bending the curve to fit the front or back crotch, I laid the curve on a manila file folder and drew the curve, marking the crotch and waist ends. I labeled whether it is the front or back curve and to whom it belongs. (I use the folder instead of Oak Tag).
I then cut the curves out and punched a hole in the corner and hung them on a hook in my sewing area.
Photos coming as soon as I get some new batteries.