I tried the “SDR conform” effect and it’s quite good, although I’m not sure whether it could be improved.
Here are a few frames from “Back to the future”, 4 from my HDR to SDR conversion using “SDR conform” and the same 4 from the actual SDR Blu-ray version created from the same 4K master.
They’re slightly different, but I can’t honestly tell which is better, the SDR BD seems to have a reddish tint.
P.S.: I don’t’ understand something though, isn’t the HDR metadata supposed to be there precisely to determine, frame by frame or scene by scene, what the picture is supposed to look like?