The reason is simple: available filter is 12" in diameter.
The reason is that my personal 11" filter has been sold. I am waiting for finishing of my next sample (3-rd generation) of the 11" DERF.
No special tips. I just set brightness, exposure and gamma so, that I see maximum details here include spiculaes. If needed I use 16bit recording mode. Then several "curves" tweaking again, for maximum details and shades visibility.