Zenith and degauss (and also HV regulation)

[nasadowsk]

After vacuuming the floor in here while waiting for my shirts to dry (Yay single male life!), i was wondering:

When did Zenith get auto degauss? I know RCA had it with CTC 16x. Did any Zenith roundies have it?

And also, when did Zenith start using pulse regulators in lieu of the ever-popular 6BK4? And naturally, did any of their roundies use it?

Bonus thought- does anyone know the logic behind the wacky power rectifiers used in their first color chassis?