After the Mabel disaster, I began my Moneta project by tracing a few inches of waist from the front and back bodice in both L and XL sizes.
As usual, I fall right between L an XL on the size chart (why is there a gap?) except for my waist which skewed all the way to the top edge of XL. After tracing my mini-test pattern, I then cut strips of material from my main material, after first checking that it was an area of "extra" material. Then it was a matter of sewing them together and trying them on to see which one fit. Knowing that the XL was a much better fit than L gave me the confidence to continue on with the project.