Thanks. I have emailed Bikegang and asked him about the speed set a few times but he has not responded. I put a 10-speed cog 16T on but it fit too loose so I went with his 17T. His set fits fine. Interestingly, 10 and 11 tooth Shimano cogs have the same thickness but different spacings. A friend has a box of loose cogs so I may have another go of it.