In butchering my buck I measured for the form with the skin on. McKenzie says I should subtract two inches from my B, C, and D measurements. That seems like a lot since I pulled the tape super tight. The A measurement was 7 5/8. I didn't get a B measurement but C was 21 1/2 and D was 23. I have the cape almost done but before I put it in the freezer I measured the cape and found that the cape was only 18 inches in both the C and D measurements. Apparently it shrunk in the four hours that I was working on it. What size form should I get?