Looked at the guts of the hand crank backpacking flashlight and hooked up a drive shaft to do some initial measurements. I was able to use a weight of 350 g with a drop of 1 meter to drive the generator for approximately 6 seconds. This gives me the baseline numbers I need to calculate how much time I should be able to run the wall sconce for using a weight of 10 kg and a drop of around 2 meters.