I have since managed to get it to run with about 3 1/2 lbs of weight. I spend quite a bit of time making ti run more efficiently. I have several tricks. To minimize sanding I first mill the gears with some backlash. I do this by cheating. When creating my tool paths I set the diameter of my end mill to a little less than the actual diameter. Cut 2d then calculates the tool path for a tool with a smaller diameter but when I physically cut it I use an endmill with a diameter of 0.125 in. This usually gives me gears with some backlash and almost no binding right from the get go. The other trick I have is not to finish the gears at all. If you are using baltic birch for gears, it is so dimensionally stable that swings in humidity really don't matter and the backlash is enough so that the gears will not bind due to expansion of the wood. Some finishes do not completely cure. Oils and varnishes on the teeth can lead so a large friction issue. On a microscopic level they often make the wood "sticky". Bare wood is better. Another trick which I am sure you already know, is sand, sand, sand. I usually start with 220 grit belts on a scroll saw. Then sand by hand up to 600. Then I rub two pieces of 600 together to get another higher grit and then sand with that. My arbors are 1/8 brass rod. There are no bushings in the frame. I polish the brass starting with 600 grit up to steel wool. Every bit of polishing counts.
After the clock has been assembled, and working, I dissassemble and finish the frame, pendulum assembly, and weight with several coats of tung oil varnish. I stay away from the arbor holes and finish around them with a q-tip. I just picked up a nice tip from clayton boyers blog "clayton boyer tocks". If your clock is running but seems to stop every now and then, there is probably an issue with internal friction on the gear train somewhere. I marked the teeth and found it always stopped at the same position but couldnt seem to fix it. He mentioned using silicon spray in the problem area. I used a cotton sway to put some silicone spray on the problem teeth and viola, a clock that now runs around the clock 24 hours a day for 2 1/2 days.