If you're talking about a couple of months, I'd wait. Expecially if you are buying a custom tailored kilt for big bucks. The buckles have a good 1" plus-or-minus adjustment, but why take a chance on the hips not fitting as well. If you are losing that much weight, you'll change of lot of measurements in the process.

On the other hand, if you are buying a stock kilt, it might not be such a big deal if you change a little in size. I'd advise going for the smallest size you can manage now since it will loosen up some as you continue to drop the pounds.

And above all else, congratulations on losing all that weight. Your dedication and perseverance speak well of you, and you will benefit in you health for certain.