I agree with Tiny. While seated the pleats aren't visible anyway, so an unpleated wrap with a traditional kilt apron in the front would be just the ticket. That way you're sitting on two layers of totally flat fabric, and that would be medically superior because it would allow just enough space for air to circulate between the skin and the seat material (nylon/leather/etc.).

Single buckle on the right, velcro beneath the waist band on the left, either simple tabs or a cinch strap. That's how I make mine.

And I for one would be happy to correct anyone who ridiculed the wearer's garment as "not a real kilt".

And just imagine, since you'd probably only need two yards of fabric for one of these, you could get four for the price of one tank!