Sizing a beaded slip-on cuff can be a challenge...

So much depends on the tension with which one beads.  My beading is neither too loose nor too tight and that's a huge plus. I usually use a tape measure to wrap around the widest part of my hand and I compare that measurement with a bangle-sizer band fitted over my hand. The bangle-sizer band is rigid and unforgiving, whereas a beaded piece is flexible and will tend to stretch over time simply from wear. Because of this, I tend to follow directions for the smaller size. Although the bangle-sizer band shows that my hand measures 8 1/4", I find that the finished measurement of the small size (7 3/4") ZigZag design fits my left wrist very well.  It is very snug as I inch it over my hand little by little, but once on, the ZigZag cuff stays put on my wrist with just enough room to fit comfortably on bare skin or over a light-weight sleeve. I find that the ZigZag cuff is actually the most comfortable to wear compared to other designs I've created.  It doesn't get in the way of typing (I do a lot of typing!) and I can slip a coat sleeve over the ZigZag cuff with little effort or having it get caught up in the fabric. My "Parrot Fish" Cuff (inspired by RickRack in CGB) is shown below: