Ah, I took the easy way out today ;-) I took the group with the most proficient riders, and got to work with the easy-peasy stuff, while the two others did a lot of support on the others. And yay! I think everyone is now actually getting there. maybe not riding all alone yet, but progressing to the point where they can partially handle the bike by themselves, and work on balance. Having itty-bitty bikes available was key, just to start with.
Deep down my frustration is probably an ego thing. I would like to be the one who just "makes it all happen", ya know... but it just doesn't work that way. 
So, in answer to my own question: "how do you teach an adult to ride a bike?" I'd say: Put them on a really small bike. And don't move up until they feel confident.
Last edited by lph; 09-18-2013 at 10:44 AM.
Winter riding is much less about badassery and much more about bundle-uppery. - malkin
1995 Kona Cinder Cone commuterFrankenbike/Selle Italia SLR Lady Gel Flow
2008 white Nakamura Summit Custom mtb/Terry Falcon X
2000 Schwinn Fastback Comp road bike/Specialized Jett