I had a lot of time to experiment collecting data in different wavelengths and stacking configurations. Here are 3 disks, excuse the orientation. I had to really push the gain to around 260 to fill the histogram. Unfortunately, it made processing the triple-stacked image difficult to process. I also noticed a more pronounced grid pattern on the 178 chip. I'm guessing the more narrowband wavelength will produce this artifact. The single-stacked version had problems with even illumination no matter what I did. I tried a flat and that didn't work very well so all are without a flat frame calibration.
Equipment used: Lunt 60 mm pressure tuned and 2 Coronado 90mm DS etalons.