Now that Clock #3's escapement seems to be working, I replaced the center pinion with a v-pulley. I made the v-pulley from two 1/8" plywood disks in which the edges were beveled in the lathe. I used hot glue to adhere the disks together, and used a heat gun to ensure the pulley was evenly glued. The v-pulley was secured to the center wheel by a pin. It seemed that this would grip an 80 lb monofilament fishing line if a counterweight was used. The line settles into the groove for an effective radius of 0.75 inches. The clock ran for over an hour on 3.25 lb drive and 0.5 lb counterweight, which works out to just about 2 inch points of torque on the center wheel.
I also noticed previously that escape wheel wheel drifted up on its arbor, so I added a small wooden washer cap that press fit to the arbor. This seemed to work well enough.