Something to note - if you follow the one on thismamamakesstuff the measurements really only work for a chair with slats in the back to fed the back part through (like in the picture). I've tried mine with a couple of chairs without backs and it isn't quite long enough, though it may be I that Chloe just has a very rotund bally. The one made by jill has longer measurements so is a bit bigger around the middle when using an open back chair, but will probably be a bit more versatile with different chairs. If you have a long enough piece of velcro it doesn't really matter how far it wraps around the tummy.
I didn't have the fat velcro used in the second blog I mentioned so I did a double row of 1" velcro.