I didn't test the ratio of my ruffles, but adjusted the foot to 1 on the top option and wound the lower screw to 6 and just went for it. I was folding the lawn ruffles in half to save hemming and boost the somewhat limp lawn. It worked well in respect of the boosting, but not in saving time avoiding hemming. Because the 2 layers wouldn't feed through the ruffle foot together without basting them together, and then I had to press them flat before ruffling, so the process only saved me the time it would take to belt along the edge with an overlocker (which I'd then turn up and stitch down, eyeballing the turn up the whole way. It's a ruffle - on underwear - so doesn't require absolute precision in the way a corset requires precise seam allowances. I did say how much I love my ruffle foot. Here's the back section of the ruffled petti - I'm only putting the lower row of ruffles on the front section.
I also got the blouse/chemise cut & started yesterday, though I didn't get the collar made & inserted. I'm doing that before inserting sleeves as sewing the collar into an oval opening be easier while the body of the chemise can be flat open. NB there isn't a CF or CB opening. No buttonholes down the front makes it easier, and hmmm, that reminds me that I must get some buttons out of the button box for the 2 cuffs. They got completed yesterday.
I've got tomorrow off work, going to get the corset hardware, have a dental check up and sew most of the afternoon. I'm aiming to get the petti & chemise finished, and the skirt hemmed - it needs turning up and the crin inserted before stitching down. I can prep the waistband later in the evening while I watch TV - got the can can skirt up from the grotto so I can replicate the pleating.