Sasha-- I didn't use grommets on my Ariel bodice. I made it a touch big with a zipper. Then I made a narrow loop of fabric, like spaghetti straps, and cut it into 2" pieces to use as lacing loops. Ugh, I'm not explaining it well. I sewed the loops into the back seams on either side of the zipper and laced through them. It meant I had a zipper so the back is fully closed, but I could pull it as snug as I needed (which has been GREAT with my fluctuating weight!).
You can't see it in any of my Ariel pics, but I did the same sort of loops for the lacing on the sides of my Ghibli Lolita. I hope you can see what I mean from this pic http://www.facebook.com/photo.php?fb...pe=1&th eater
The loops are set into the seam on either side of the zipper-- not right at the zipper, but the next panel over-- so the center third of my back has laces crossing it. When you sew them in, decide where you want them, pin them to one of the panels, then baste them to the panel before you sew it to the other one. Double stitch those panels together for extra strength and they won't come out.
The real benefit to using the loops is that you make them from the same fabric (cut it straight so you don't get any stretch-- don't use bias strips for this). And you can use scraps too-- I usually make sure I'm using at least 6" sections so I get at least 3 loops per turned strip. A 2" wide strip, sewn about 1/2" wide, then trimmed to about 1/8" - 1/4" seam allowance (you need it wider if your fabric likes to fray) is about the right size. So anyway, it matches! Your lacing can be whatever you want-- a really long turned tube, grosgrain ribbon (satin would be too slippery), or basic cotton twill tape which is what I used. You can't lace it *quite* as tight as a corset with grommets, but I can still get a pretty good shape with it. It's my favourite bodice by a long shot!