Fixed Gaussian fits. Now pdf is no longer influenced by ADU values outside of specified range (currently mean value \pm ~75 although have also experimented with FWHM)
This log plot clearly shows that the distribution is not very 'even' either side of the median ADU value. Quantitative reasoning to tightly restrict fit range.
Y axis scale fixed.
Have started to explore 2D gaussian fit. Here is an example plot using 2D random distribution: