Feedback from test spinners has been wonderful. It performs flawlessly for a wide range of rpm; from 400-2000rpm it's exactly like little Sparrow, and from 2000-4200rpm it becomes a production level cotton or silk powerhouse.
A variety of bobbin designs are being tested now to see which is the best of the best. Hoping to get the first production models made in about 30 days.
Sea Island Cotton test spinning by Longdraw James. Approximate WPI is 100.