FWIW,

I use my DuraTrax Piranha Digital peak charger ($50) to charge my batteries. I set it for 100mAh capacity, and 200mA charge rate, 6mV peak detect. It takes about half an hour to charge the cell, and the car will run for well over 15 minutes with the red (2.6?) motor. I also installed a small on/off switch, so the battery doesn't drain down all the way when I'm not using it.
I had to cycle the cells a few times before I got close to the rated capacity (100mAh, and 80mAh). I used a #112 flashlight bulb as a discharger, the #112 is designed to run on 1.2V, it draws about 220mA, so it'll drain a cell in less than 30 minutes.
I guess I could bump up the charge current to charge them faster, but I figure the batteries will last a whole lot longer (more total charge cycles) with the lower charge current.