Please tell me if i have this right.

Well I don't know much yet but what I am seeing is that kilts seem to form a arc or semi circle. The inside diameter has got to be the waist with the aprons laying straight and form "square wings on the ends". The outside diameter is based on the length of the kilt and it seems a simple enough geometry problem but I just want to be sure. I have seen a lot of different ways to sew a kilt but it seems like most of the time everything is glossed over. Do you have a good online resource for a kiltmaker without a sewing machine or seamstress skills?

Thanks.