Thank you all for responding to my request.
(I'm sorry for the delay in my reply; I was working on some performance improvements to the analyzer tool, and also trying to understand an anomaly I see when I process data from color sensors.)
But I've just created a folder on Google Drive that should be writable for anyone with this link.
drive.google.com/drive/folders/1nHlqDTHz...ofudq?usp=drive_link
I assume that Google drive will allow you to create sub-folders in this shared folder, so it would probably be best to create a "home" folder for yourself. And then upload zip files of your bias and flat images to that home folder.
If you plan to create new flats and bias images for this effort:
Remember that I will need two of each file type, (2 flats and 2 bias), for each gain value being plotted.
I use file naming format like this /%t/%T/%F/%t_%T_%F_Gain_%G_Offset_%O to help me distinguish the files. (But I can jut read the fits header if need be).
For flats I've been setting the calibration option for the ADU to 29000. But this is probably not critical, as long as the value you use is reasonable and consistent.
As I mentioned, I'm using a dimmable LED panel for my flats. But to reduce the brightness I ended up inserting about 30 sheets of printer paper between camera and the panel so that the exposure time for flats is around 1 second. But when I image at with higher gain values I've had to add a few more sheets of paper because the exposure time can fall rapidly at high gains.
I also found that my cameras leak light in quite badly. I've been creating my images in daytime, and find that I need to cover the camera with a dark cloth to avoid unwanted light in the exposure.
Thanks again for your help!