I have used that pattern but I started with a medium size. I think they turned out GREAT!
: I just opted to not use velcro or snaps and use pins. I do not really go for the aio though because of the dry time. I did however make a cover using a shower curtain in the middle as my waterproofing. That works out great for me. I put the lining in the middle to avoid having any tears in the vinyl.
With Summer coming up I am not planning on using a cover at all. I don't want his bottom getting too hot. And I doubt he will be wearing pants or shorts during the day unless we go somewhere. So I won't have to worry much about leaks.
I think how I avoided having the pattern come out too small is because I have a tendency to work big anyway.
BTW I do have a pic on my own website showing what my diapers look like after I tweaked the pattern and added some touches of my own.www.wk.net/sew4you
I don't have a ton of pictures up yet, I have taken a bit of a break from sewing for a while but I am getting back on track now.