A closeup of the overhead feed showing the 1/2" Pinion drive to the small Gear Ring, in place of the earlier 2 1/2" Gear. The double 2 1/2" square plates on the tower are there to improve the upper tower's torsional rigidity - a modest approximation to a closed box structure without actually having one. It works surprisingly well.

After watching these videos, I have now replaced the open 1/2" Pulley at the left with an enclosed version - just to allay any fears that the yarn might jump off!