Any question answered...

please can someone recommend/sell me a wide footed 17t 1/8th fixed cog... the one I have is too narrow and doesn't stick out enough for the lockring to hold it - or otherwise recommend me something to put behind the cog I have to space it out a few mm.

Strange that the sprocket's too narrow. I've only ever seen this on cheap shit sprockets. Dura-ace sprocket's aren't that expensive.

BB spacers also fit

edit: ^^ bah I was doing some research, then started drooling over Di2