I made this one, it was pretty easy to size it up to 1X. I adjusted it to circular knitting so I wouldn't have side seams, I also added X stitches to the cast on to make it big enough. Since it's knit from the waist down, it's easy to try on as you go. You increase at the side seams, so I put markers at the side seams and did the increases either side of the marker how ever many rows it said. I think I started the eyelet rounds a bit lower, too.