How to estimate Ruffles and Gathers

I remember looking this up for some dresses we were making in Grad School, and for some reason it's always stuck with me. Usually a good ruffle is between 1.5-3 times the length of the area you're covering, depending on the fullness you want and the weight of your fabric. When using the ruffler or gathering foot to join and gather or ruffle at the same time, here's what I've figured out. Photos coming soon. Take a sample unruffled piece and mark it clearly with 1" marks along the edge. Then use it to calibrate your ruffle and get one you like. Then mark it again with 1" marks for about 3 or 4" and measure how many original 1" marks within each second 1" section. This will give you the ratio for your ruffle. So if each section has an average of 2.5 marks you have a 2.5:1 ratio. And if you have a 15" straight piece to cover then you need 15 x 2.5"= 37.5" But also add 2" or so of "slop" at the beginning where it isn't ruffled yet and about an inch for your 2 seam allowances. What do you like to use rufflers or gathering feet for? Let me know if you have any questions in the comments.