I've revised my settings somewhat in light of the BvS gunfire muzzle scene.
Previously, I had min scene duration set to 0, but I think 700 works well for that scene. I can't see any visible dimming during the scene or the switch to the next scene.
I don’t think that 0 is too bad for min scene duration. Yes, there is intermittent dimming/brightening when the muzzle flash occurs: it goes bright - dim - bright -dim. However, your eyes are somewhat distracted by the muzzle flash, which is occurring so quickly so you might not fully pick up on it. When set to 1, the scene stays dim in-between the muzzle flash, which is more noticeable than 0 imo as it goes bright -dim and stays dim.
With 700 it works well.
My other settings for the brightness speeds from left to right are
0 - 2 -25 - 150 - 225 - 250 - 450
Scene change threshold is set to 30
As for my thinking for reducing the 20% diff to 2 (as opposed to 5)
If I look at Ex Machina and record the dynamic target at intervals during that scene:
My settings (above) with 20% diff = 2 / With 20% diff = 5 / Neo's setting
192 195 192
191 190 187
190 188 183
183 176 175
182 179 182
184 187 199
187 203 210
My setting with 20% difference= 2 is giving me more stability i.e. the range is 182-192.
With 20% diff = 5, the range is increased from 176-203.
With Neo's setting the range is increased from 175-210.
Of course, this is just one scene.
I also looked at the Mad Max flare scene (frame 25963), which can be too volatile if I set the 50% difference too high (which I'd set higher for a different scene). With my current settings the scene ranges from approximately 310-344. If I set it too high, it can go up to nearly 400 and you'll notice a dimming in the sky as the flare goes off and then it brightens again. Neo's settings were fine with for this. The range was only around 10 nits higher.
My settings are also quick enough to react to Wonder Woman and the quick brightening/darkening after Doomsday fires that blast at her.
Still work in progress atm. I've already revised these a few times when testing different scenes.