Awesome. Glad to see some folks still remember the half step dance with granny. I still have a Motobecane tandem stored away with that gear design built up from the TA Cyclotourist cranks it came over with. I had another one that I experimented with (circa 1974-75) to make it with 4 chain rings on the front (something like 22-40-50-56) and 5 cogs on the rear (a mod'd 14-34 freewheel). I did the build work in prep for a trip across the plains and then up the Rockies and I got it working well enough, but the trip never happened due to life problems elsewhere. I do remember trying a run of a big spring from the RD arm up to the underside of the bottom bracket and lengthening the RD arm about an inch, all to help wind up all the old heavy chain. I eventually concluding that all the fuss wasn't really worth it and went back to the earlier 3x5 setup before someone stole that bike. I think the extra, extra long French bottom bracket is still in one of my boxes somewhere.