Ron,
Are you chasing a specific problem in your exciter or are you just
exercising your test equipment? How is your suppression and voice
quality?
It's been over 40 years since I fooled with Lissajou patterns on a
silly'scope, and that was in electronics school in the Army. But I do
recall that any stray signals, hum, or any distortion of the sine waves
will blur the image. Is your 1kc tone pure and clean? Seems the 20-A
manual calls for something a bit higher like 1225.
You're the first 20-A owner I've ever run across who was scrutinizing
the output of the PSN with a 'scope.
I always just tweaked everything for maximum sideband suppression
and let her rip.

When I built my first SSB phasing rig in 1958 (the infamous W2EWL
design), I borrowed a friends Heath AF generator and silly'scope, and
spent hours trying to get it right.I finally learned to do it by ear by
adjusting everything for minimum modulation with tone input while
listening on the station receiver.

I acquired my 20-A along with a Lakeshore VFO in 1964. It is still my
primary station exciter today. I use it to tickle the grids of a trio
of paralled 807's or the final stage of a Johnson Valiant.

John