I was a bit skeptical of the overall sizing chart (and still dont’ have my band) but here is how I approached tracking down what I hope to be the best fit.
I cut out the sizing chart print out, the key areas to cut accurately are the top of the large mock watch head and the bottom of the straight flat band area. really just to two parallel Lines are the key measurement points.
then, I took one of my fluorlastimer bands from a sport and a nike watch (of course anyone who is new to an Apple Watch won’t have these) and noted where I wore them regularly. Which notch. I do shift on the Nike bands between the 4th and 5th depending on if I’m working out or not (and if i’m using a forearm HR monitor or not)..
Then I took the bands OFF the watch and connect them as if I had just removed it from the watch. I laid one end of the strap just BELOW the mock watch head on the paper cut out, and let the OTHER end of my connected strap indicate which number would best match my preferred sizing. It was just between a 9 and a 10 so I went with the 9.
As I said above, don’t have the band yet but once I do I’ll report back. Since I bought a “my style” combo with the Blue AW and the yellow solid loop, hopefully, if it needs to go up or down a size it won’t require the whole kit to be returned and replace. I know I’ll be keeping the watch for sure.