I am well aware of the field aberration and I can assure you it is tilt. I cannot move the Gerd any further to fix the portions of the frame that are still not squared. I plan to refactor my spacing logic to move the Gerd closer to the camera, which will allow me to fully correct the field. The collimation of the scope is excellent. Both myself and Tolga reviewed it together (thanks Tolga! ), and we made a few adjustments prior to any of this data here for PacMan being taken. The Wizard data was before the collimation changes. Those changes were rather minor anyhow, and the more important one was a fix to the spider to get the spikes to be more clean. Dall Kirkham telescopes are not difficult at all to collimate. Especially since their secondary is spherical.
I would not have this field aberration problem if the camera was made with a sensor not skewed so terribly. It sucks, but for this project I had to make a tradeoff on wasting more nights on turning screws on the Gerd or getting the field close enough and getting some data. After all, we don't buy telescopes for endless nights of troubleshooting.
I have compiled another set of masters, one Drizzled and one not Drizzled with the entire OIII data collection. The previous masters were 33 frames, and this is 153 frames. I do want to tell folks that the newest version of PixInsight is a much better performer than the previous, even on Windows. To have 153 frames in Drizzle finish in 12 minutes is pretty solid performance over what I have seen in the past on the same system, which was about 20 minutes.
The new masters are in the same share as before.