If you sew corsets you need lacing strips. Sew along participants who don't already have a pair will want them, and I need a longer pair, so it's the perfect time to explain how to make them. Start with two rectangles of fabric, mine are 18"x 5." Use something strong, like canvas or coutil. I'm using denim, which can stretch so if you use denim make certain it doesn't have a lot of give. Fold the long edge over 1 inch and press.
Then fold again 1 3/8 inches and press.
Here are the two strips folded and ready to sew.
Sew a seam the length of the fabric, 3/8 inch in from the outside fold. Use a long stitch length, no need for minuscule stitches here.
Sew a second seam 3/8 from the other fold.
Sew one of the open ends closed by stitching across the the seams just sewn. Mark the grommet spacing. I marked every 1 inch starting 1/2 inch from the end, but you could space them out more if you like.
Set your grommets.
Slide a bone in the the outside channel and sew the remaining open end closed. There is no bone in the other channel. Why leave an empty channel? It just looks more balanced that way. It's the same width that the lacing will be on finished corsets. A second bone could be added, but it's not really necessary for fitting mock-ups.
Serge or fray check the raw edges of the fabric and you have lacing strips. If you only have boning on hand for the corset we're making for the sew along then use the longest bone you have in the outside channel and just don't sew the end closed so you can remove it and use it for the finished corset.
Not that difficult at all. And very useful. And good grommet setting practice if you've never set a grommet.
Suppose you only have enough grommets to construct the final corset, or you never plan on making another corset again, it's alright if you cut small slits, like buttonholes. They will fray a bit and it won't be as easy to lace but it will work. But there will always be more corsets or costumes that lacing strips will be handy for. Go ahead an make a pair!