Hi Andrew,
I think you’ll need to discuss the delivery in greater detail with the team, but I would imagine that if they are finishing 2.40, they would want to view everything the whole time in 2.40. As you said, the most useful things for them to have in the end would be:
1. 1920×1080 HD Master (with 2.40 letter boxing)
2. A 2048×858 2K Master for DCP (which is 2.39 or so)
Because Resolve is resolution independent, you can change from one project resolution to another pretty easily without your framing getting screwed up (as long as you keep the same aspect ratio and your scaling is set to one of the “fill frame/fit to frame/etc.” options). There are a couple ways to do it – one way to approach these end deliverables would be by setting up a 1920×1080 project with a 2.40 masking, and making all your framing adjustments based on that while you monitor in 1080p.
Then you could output the 1080p version from your 1920×1080 project. After that, turn off the masking, switch the project to 2048×1152, and your output to 2048×858, no resizing. That would give you the 2.39 2K version without changing the aspect ratio.
As far as matching the editor’s reframes, we match them all exactly and then make adjustments with the clients present. That way they only see what they are used to seeing until you broach the subject.
Cheers,
KC
Prehistoric Digital