I do dusk and dawn flats with ACP automation by preference. If that's not an option I use a Gerd Neumann EL panel. I like to get a minimum of around 500K e- total for each filter (about 12 flats at 30K ADU with my U16M camera but it would be a lot more for a camera with shallower wells). The 500K e- number is based on the work by Richard Crisp. Not sure if this the paper you were looking for, Greg?
http://www.narrowbandimaging.com/inc...3_expanded.pdf
Cheers,
Rick.