So...progress...in fact, a big step!
Using my trusty counter I did find the Hor freq coil was set very low. The coil after it, which acts as a kind of range setter was way off as well. Having dialed these two coils into range, 15.500-750 ish and the H lock into a mid position, i was able to get rid of this pesky Horiz sync problem and my multiple pictures have gone away.
Big learning moment! Give the dang frequency counter some love!
Now I can see the line, crosshatch and staircase patterns.
Vertical lock remains a problem, especially as the control no longer affects anything. Vert linearity and height work though.
Please enjoy these progress pics:
https://ibb.co/fY1pqX4
https://ibb.co/5W7QDPd
https://ibb.co/rp1WJfg
Adding a short video
https://youtu.be/9mdcOzbqWaw