I've made the same mistake. Twice. I don't learn so good, I guess....

The good news is, it works just fine when it's just a little stretch. Stay stitching will be your friend on any curved seams. I didn't flat line skirts or other terrifically large, loose areas. Actually, I think the stretch was an unexpected bonus on the train of the loose gown I did -- people kept stepping on the train (because modern men can't be bothered to be mindful of a gown's train *or* their own swords most of the time), but the stretch in the fabric helped prevent an annoyance from becoming a catastrophe.