This is something I have also asked as I seea lot that are to small . Having had a look at quight a few I fined that making big er can be done if they have folds at ether side of the kilt but most do not and if they do they are quight small/

However I have made big kilts small many times and have 4 kilts now that were a lot bigger and now fit .I simply move the straps and buckles and wrap them round more . I'm not saying they are perfect as the pleats fold under the front apran . But I don't see a problem with this and they retain the weight ,I didn't want to start cutting bits of.