Re: How many options for centered sprocket?
LOL, I'm sure Jim is just waiting to launch onto this one...
HT2005, Jim, the Manic Mechanic (Creative Engineering) offers a great product that I've heard nothing but good reports on but to answer your question there have been successful installs using a disc brake rotor hub. This takes some skill to adapt and not something the casual weekend mechanic should tackle. There are other clamp on, or socalled clam shell style of adapters available but I have no links for you at the present. maybe someone else who has tried one of them will jump in. Good luck.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"