You guys are AMAZING!! That made things so clear now. Thanks very much.
The need for the ferrite horn ring is to get center very intense due to two factors: to the horiziontal windings getting in the way due to high deflection angle CRTs and low voltage & low current of vertical IC?
Only two makers I had to replace or service yokes with alarming frequency were philips with bad vertical or horizontal (made top area to misconvergence due to bad yoke (what the cause?).
JVC CRTs with buzzing noise was drill holes and dig out foam pads (carefully!) in interior side plastic for varnish to get inside (required 3 dips that takes a week to do).
Only one CRT I had to replace for bad yoke due to RCA bonded CRT yoke. Shaking a fist at RCA for this foul manner meant CRT is at victim to possible bad yoke. (Fault was smelling of ozone while running).
Cheers, Wizard