After a week of testing my little Raspberry Pi standing in for a grandfather clock sized master clock, I pulled wire through my office wall and properly installed this 1939 Standard Electric Time Company school clock. The clock never missed one click the entire week. This makes me happy.
We have insulation in every wall of the house. I will not be pulling wire through many more walls and instead will come up with a different plan for the placement of each clock.
A small accomplishment. I am pleased.