"Best practice" is to have the client visit the shop so that I may put the kilt on him and then mark exactly where the left-hand strap - and the right-hand buckle - should go, but that's not always possible these days, is it?
The one thing that we MUST remember is that when we first measured the client he was wearing a shirt and trousers, and therefore that measurement represents the INSIDE circumference of the kilt!
This is why a strap or buckle will often be too far 'short' when the client puts the kilt on - even though the waist measurement was right.
It took me a long time to figure that out....in fact that 'Ah-HA!' moment might not have come to me were I not posting these videos.
It's true - if you want to thoroughly 'learn' something you need to 'teach' it