Thanks guys for the guidance (and possible replacement yoke)
I looked at the yoke, checked the resistors on the vertical windings, high but not crazy, and the capacitor I replaced on the horizontal windings was a 47pf and I read it wrong and replaced it with a 470pf. D’oh! Put a crusty 47pf ceramic disc on and now have normal-ish deflection. That stupid drive line is still there but not as bad and the width is still uncontrollable but we’re doing a lot better!
Excuse the blanking in the photo and crooked yoke