There’s no need to do it that way, when the theatrical blu-ray generally has much less DNR (for live action), so you edit that to match the DE edition. This is what I will be doing.
Sure, you can do that and it may end up better looking, but by doing what I just did I have quite nice looking Director’s Edition made in half an hour (+ re-encoding) without any editing required and with grain in place also in DC exclusive VFX shots.
Can you tell me why popular films like the back to the future trilogy uhd and the et uhd haven’t been regrained like what you’re doing for Star Trek the motion picture’s directors cut?