Well.... I ran a thread about this a while ago (https://www.physicsforums.com/threads/astro-image-stacking-optimize-dss-image-stacking-and-post-processing.963947/). I'm happy to send you a RAW image to play with- PM me with details.@Andy Resnick & were the TIFF's 8 bit per channel (24 bit)? I ask because if the TIFFs were 8 bit per channel you potentially lost a lot of sensor data in the RAW->TIFF conversion. Would you ever consider sharing one of the RAW files so I could take a look at it with my image conversion software? A lot of Camera RAW files are 14bit or 16bit per channel.
The 14-bit RAWs are most likely converted into a 16-bit/channel TIFF before stacking. The stacked TIFF has a 32-bits/channel format, but in reality there's about 23-bits/channel of information. The magic happens when compressing to a 16-bit/channel TIF for non-Deep Sky Stacker post processing, for example denoising. The final step is another compression to 8-bit/channel which I save as a jpg because filesize.