late 60's zenith vs. RCA vert
 

zenith with its 6BE5/6BA11 vs RCA (and clones) with the 6GF7.

Seems I have less problems with the zenith, esp on setup of linearity and height as well as more consistent line spacing (seems the rca is a bit fussier about the vert hold to eliminate line pairng).


just an observation.

The Rca circuit is prone to drift. Make sure that you've recapped the vertical section - especially the high voltage film caps. The 4 RCA sets I have all had leaky caps and the vertical would be an absolute PITA to set up after warmup. After the recap the problem was completely gone.