Well, here's my take. I am a big guy. Sporran chains and straps don't work well for me, but sporran hangers do. If I'm not wearing a belt, then I can't wear a sporran. SO- I had my formal waistcoat made double breasted with a straight hem that comes to the top of my kilt. That way, I can wear a belt with it and not look totally rediculous. So it seems to me that while the rules of fashion should be adhered to, the rules of practicality trump them.