Flexure Possibly Fixed?
The image shows the results. Pretty good and it blows away previous work. There's still a tiny bit of wobble in DEC, but that's another task altogether and it's fully within the range for acceptance.
Finally got the scope set up last night after work done earlier in the week. Spent extensive time getting good polar alignment with PHD2. The readings on the drift tool had results under 1 arc minute for Alt and Az. Drift was within the 1 arc seconds per minute range as needed for precise work.
Everything worked smoothly. I was able to get the SV70ED with the Televue FR to a precise focus and then locked down. Moving the star to the center of the field didn't require much effort and the star images remained nice and round - no oblong smears like I'd been struggling with in the past.
Used the mount at the default sidereal rate rather than the custom rate I'd tried before. With autoguiding, I'm not certain that the custom rate was effective.
Focus on the DSLR did shift slightly over the course of the evening. This is something that I expect to happen and it's not surprising. In the field, I'd check focus a few times during a session and it's only because I'm at home where I want to go to sleep is this a missed step.
I tried using the Pinpoint Guider Calibration plugin on Maxim and was annoyed that the Imaginova control window for the SSAG was overlaying the plugin control panel. This is unavoidable as the two panels probably come from the same resource, so the positions are locked together. I also tried the Multistar guider and was unable to get it to work for me. I think that the SSAG doesn't have clean enough star images to make it worthwhile to use. Many times I am unable to see the stars that Maxim ends up using to guide. The stretched field is just too noisy to pick out the proper stars.
I've also re-enabled pulse guiding over ASCOM. I'm ditching the ST4 cable from the SSAG to the mount. The way I read the information about pulse guide is that it gives specific guide information to the mount without having to wait for start/stop signals that could be interrupted.
Great results in the end! With the guider chugging along and giving super results, everything just worked! Looking at the graph above, the jump after the first few images is because of playing with the multistar guider plugin. For a while the scope was unguided. Everything afterwards seems to be as good as I've ever seen.