Re. Jocelyn Lovell was the rider who rode using this drivetrain.
I know someone who saw Jocelyn do this, but he said he did it with a freewheel on one side and a fixed cog on the other, with fixed cog wound off a bit so it would wind on while using the freewheel, then when the fixed cog got fully engaged the freewheel side would just freewheel for the rest of the race. I don't know which cog was on which side, but it was ingenious, and from what I hear, typical of Jocelyn.
Brian (there are no hills in Ontario) Booth
Toronto, Canada