Under apron pleat on the X-Kilt
I am finally started on my X-kilt and have a question. The Appendix 1 diagram shows, from the right hand side, an over-apron edge hem allowance; the over apron of 10"; then the under apron pleat 12" the the inner fold etc. Steve's excellent (and often entertaining) instructions direct me to measure the over apron, (which in my case turns out to be 8" instead of 10") but do not explain where the 12" under apron pleat comes in. Is the 12" is just a random measurement? What am I missing here? I don't want to start sewing in pleats until I know I am not going to regret it. :)