Welcome Charles!!!

I don't think weight has any bearing on kilt wearing. There's a wide weight variety here, and we all wear the kilt with pride.

The thing I see weight effecting is the sporran. If the sporran or the strap get under the belly it can cause the apron to bunch. I've lost a good amount of weight, but still have a belly, and I have that problem all the time, one of the reasons I don't like wearing sporrans much. Something I just haven't mastered to my satisfaction.

Sliante!
Nick