UE4 already handles light in a physically based way, so it doesn’t need the tweaks mentioned in that video (although Eye Adaptation isn’t really a replacement for physically based camera). The way UE4 handles light is what allowed them to add HDR display support pretty quickly and easily without overhauling the lighting and rendering in the engine.
If you want to get great lighting on a specific scene, I’d suggest starting with setting Eye Adapation to a fixed exposure instead. Using a value between 6 and 12 for the sun as a directional light and 1/4 of that value for the skylight is a good starting point and close enough to realistic. Plug those values in and then adjust the exposure to compensate.
The new tonemapper in 4.15 should help add the de-saturation discussed at 22:00.