Phew, crisis averted. Joann's discontinued their amazing sateen in all but like three colors, and I don't think I have any of my purple left after all, so I was screwed for Super Saturn parts. I discovered a listing on eBay that seemed to match the specifications the Joann's purple sateen had, so I ordered a yard to sample. It is indeed the discontinued sateen. *u*
Here's the listing, with lots of fun colors!
I really, really can't recommend this sateen enough for fuku if anyone's shopping around for fuku fabric; the sheen is gorgeous in person, the fabric photographs amazingly, and it's soft but durable (I accidentally dribbled a little Coke on my skirt, but all it took was a gentle spot cleaning with water and letting it dry, no stain!). It just requires more frequent ironing than if you were working with a poly/cotton blend, since it's 100% cotton. It's also no-stretch, so if you prefer that for glove bands I'd look for a 97% cotton/3% spandex blend stretch sateen.
So so happy. *u* Now I just need to resample a couple dark brown stretch sateen fabrics to get a match for the bows, I'd have enough of that fabric left over if I didn't insist on doing the tails in a slight Super Sailormoon-esque flowy manner like how the Inners' tails are in this image