I may have recorded the spot noted in recent captures by Pete Gorczynski on the lower right of the disk--- the longitude is similar to that of his result taken earlier that same morning. The camera was RA drift aligned so that celestial north is up--- which means that Neptune's N pole is pointed at about the 1:30 clock position. Although I didn't capture the pronounced brightening near the S polar region in results shown by others; the northern region has stronger limb darkening than the southern region.
The use of the ADC was due more to an experiment that night in using a W47 filter in my filter wheel to adjust the ADC while using the camera--- the deep red/near-IR leak of a W47 filter causes images of stars to be formed in both the deep blue/near UV and the deep red/near-IR. When adjusting the ADC one can see a star split into two components which can then be merged to indicate proper adjustment. In practice, imaging with a near-IR filter like the Baader 685 gains little benefit from an ADC --- it really only helps the shorter wavelengths noticeably when RGB imaging, so my next Neptune session probably won't include the ADC.
If I get another chance at Neptune soon I'll probably use my DMK21 with the more near-IR sensitive ICX618 CCD. Hopefully that will capture more of the deeper near-IR. And if all goes well in a couple of weeks I hope to be using my long-awaited 14.5" f18 Dall-Kirkham instead of the C11.