I may have the horz prob licked,
It seems to have stopped but I need to get a fresh look at it later.
The pcb has little solder fingers on it that touch the bare metal chassis, on the sweep board
The horz osc has a solid wire ground, while the vert osc and vert amp use pc traces that go to the ground thru these little fingers.
I was able to clean up the wave by running those two tubes heaters on DC, the horz osc did not need the DC hmmmm.
anyway all the sweep board tubes now have a solid wire ground returns, AND cleaned and tighted up the pcb mounts to make sure the little solder fingers are firmly attached to the chassis.
I got a couple books so far, one is a waste of time, the other mentioned horz "weave" and went on about filament grounds
Not sure if the "weave" is the same symptom as I have be trying to describe, but it was nice to see a meantion of the same solution.