Grant, I do appreciate your informative explanations. I am just trying to get my head around a simple dynamic model for the solar system, and all these angles and details are essential. Apologies if my questions are basic. I am always eager to see references.

So far we have the SSB buzzing along at LSR of ~200km.s-1, plus 14km.s-1 as we depart from the great ring, planets forming anticlockwise helixes with SSB as their Z axis, Earth annual return distance 42 AU, the leading edge of the system pointed down 60 degrees and with zero yaw against galactic centre. So the solar system keeps in a precessing plane with the universe while it orbits the galaxy? For a minute I had in mind it spinning on a string entrained from the galactic centre. With the apparent movement of the galaxy around the earth over 240 million years, the galactic centre must drift north or south across the ecliptic every 120 million years.

Is the galactic centre ever near one of the earth's celestial poles?

If the plane of the zodiac against the galaxy is fixed like the tilt of the orbit of the earth against the sun, does this mean there are 'seasons' in the galactic year, and we are now at an equinox, just as the sun crosses the equator at the equinox?

On this model, in 'summer/winter' in 60 million years, will the galactic centre have moved into the south celestial hemisphere or the north?
Thank you I earlier corrected myself from spiral to helix, I just use spiral as a simpler term - knowing it is less accurate! Makes me think of a millipede crawling through space.
Does this mean our whole spiral arm is flapping up and down with this period?