After several tests, I found 3.7 to be the best aspect ratio for a single row. However, when I got to testing 20g I found that my closest ARs didn't really work -- 20g/2.875mm was a little too tight and 20g/3.0mm was too loose. So for 20g, I used the 20g/2.875mm for the outside rows and 20g/3.0mm for the inside and it works perfectly. Also, using a different metal for the inside row makes a beautiful mixed pattern, so we've listed all of the sizes as 2 packs - (a) outside rows and (b) inside row - to give you the option of mixing and matching. All of the metals and combinations I've tested so far work perfectly and should be completely interchangable.
Another neat thing I discovered is that you can taper from one size to another easily just by starting with the center ring. So, for example to taper from 16g to 18g, just use the center ring from the next size down as your last locking ring. For 16g, use an 18g/3.75mm for the last ring (the point) and weave 18g from then on. Sizes for the sheet weave will most likely need to be a bit larger and I'm hoping to find the time to work on that next. Have fun and let me know if you want any other sizes or metals combinations tested.
-- Gary