Mychael, good to "read" from you again!

As for the one inch alteration, it's only a crop of 1/2" per strap, and that's minimal. Anything within about 1" to 1.5" of expansion is completely acceptable with a traditional. The "under apron" usually accomodates such an alteration with a side hem of 3-4 inches of extra material. When you get it back, just be sure that the under-apron fully extends across the front of the kilt.

To make it larger in the future may not be as simple however. It requires "re-working" the pleats to where you have enough material to extend the garment. That can be very time consuming and difficult... especially if it's lined correctly. After that the under-apron, the belt-loops, the lining, the cap, and the straps/buckles need to be matched-up to the new sizing. The toughest part is working with the material that's been cut away (under the lining) so that the kilt fits the hips without bulking/bunching. It's possible... just time consuming. That's what I'll be doing beginning in November (along with repairs and re-linings).

Since marrying a Pastry Chef, I've already had to alter my favorite kilts. The casuals are a piece-of-cake, whereas the authentic wool traditionals are time consuming. It's a lot less expensive than selling them and ordering new ones!

Let us know how they look when you get them back!