I do know that Phase One's official spec on long exposures for the P45+ are, outdoor temps no higher than 69 degrees F and low to moderate humidity. I am not sure on the static electricity but this is CCD vs CMOS.
In my use, the D800e seems to get to a threshold in about 2 minutes to 5 minutes, then the rest of the image seems to stay pretty balanced out. The longest single shot I have taken the D800e to is 30 minutes and that was just playing around, as I normally will only stack at night, max 5 minutes per shot, average 2 min. I always have Long Exposure noise reduction off (which for nikon makes the camera create a dark frame each time).
The CMOS in the D800e does a good job, however it's plagued by the same white dot issue that the D810 had, and Nikon fixed. As I have seen many D800e cameras that don't seem to have the white dot issue, it's clear to me Nikon fixed this issue on the D800 family under the covers, and just forgot to apply the fix to the newer D810. I can also state that the outdoor temperature makes a big difference in the white dots, i.e. 80 degrees or hotter and they will be a pretty big issue. C1 does an excellent job on these spots with the single pixel noise slider, where as LR can not clean them without massive loss of detail in the rest of the image.
With the IQ260, I have only taken mine to 10 and 15 minutes. Both frames at the LE setting of ISO 140. Results were OK, but still not as clean as my P45+ at 45 minutes, so I never really did anymore testing. Each time the back took the dark frame.
I have never tried stacking with the 260, due to the dark frame. If the dark frame can be disabled in Aerial mode in zero latency, I am still not sure it help much since in zero latency the back will get much pretty warm in a much shorter time frame.
Paul