Back on topic, I'm reprinting one of the wing panels that warped. I sanded the PEI sheet with 1000 grit, cleaned it with denatured alcohol (vs the 70% isopropyl I was using), and lowered the live Z by 12 microns to get a better first layer squish. So far, there is no sign of the first layer separating from the bed and I'm about 90% done. I also switched from printing all four segments in the same print to just one segment.
The wing panels are numbered 1 to 4, starting at the wing root. No separation when printing panel 2 of each wing. Once I popped panel 2 off the print bed and did a test fit. There is a slight bit of warping along the base of the panel. About one layers width from front to back. Nothing a few passes with a sanding bar doesn't fix right up.
Panel 1 still showed minor separation at the trailing edge. I could slide a piece of paper 1.5-2cm under the print. Placing the panel against a straight edge, it looks like 1-2 layers worth of warp across the base of the panel. Should still be correctable with a sanding bar, without too much issue.
Printing a single panel at a time has also removed all "blobbing". When printing all four panels at once, there is a long move from the end point of one layer, back to the starting point of the next. A bit a filament can ooze out of the extruder nozzle, just from gravity, and cause a blob at the layer starting point. Apparently, increasing the filament retraction can help reduce it if it is very bad, but may not eliminate it as even after pulling the filament back, there is some that is already melted in the extruder nozzle that can ooze. Compared to some pictures I have seen, mine were not at all bad and since doing single panel prints made them go away, I didn't muck with the printer settings.
While my printer is still nice and new and all the parts are fresh, I certainly haven't seen any of the finickiness that people have talked about with respect to 3D printers over the years. Yes, there is a learning curve and, yes, paying attention to details are important to getting quality prints, but I certainly haven't had any failures during 60+ hours of almost continuous printing.