I tend to with agree with Aspiringloser. These kinds of buckles can connect in slightly different ways, depending on brand and for what they are used. This being the case, some are easier to work than others. They can definitely be operated with one hand. I have use of both of my hands, but I have been in many situations where I could only use one to operate buckles on my gear. These buckles could be used on a traditional kilt as well. Maybe they could be put on the inside like some of the kiltmakers here do with the traditional buckles and then have a nylon strap that could be pulled with the left hand to tighten that side. The male end of the buckle could be attached to the under apron and the female to the kilt where the strap would normally pass through to buckle. After changing the direction of the apron, it seems like this would work for the individual in question.