I am making the blouse for the second time but I am having a heck of a time figuring out the casing for the elastic. I am folding half an inch over on the bottom, and then trimming that half inch to 1/4th, then I attach the bias strip to the shirt with a 1/2 seam, making it even with the line of the shoulder piece, but I just don't have enough width to fold it inside and stitch it down to hold the elastic. last time I just serged the edges and stitched them straight down to create the casing, but I know I am doing something wrong to be screwing this up. Does anyone know what I am doing wrong here? I know it must be right in front of my face, but I am just messing it up majorly.