I've been reading around the internet and it seems like this is a question which's already been asked lots of time, and it's frustrating to see there's never a precise complete answer as for the perfect workflow to follow for a roundtrip Premiere-Davinci.
A. We shot in 3.2K with the Arri Mini, (so 3200x1800 1.77). Final release will be in 2K 2.39 scope DCP.
B. The proxy in Premiere are: 1280x720. The editor sent me the XML of 2048x1080 where he also added the the 2.39 letterbox.
In Davinci I'm setting up a 2048x858 timeline - scale full frame to crop. Is it correct? And I relink my original footage to it and do the grading.
When it comes to export, I export on the same 2048x858 scale full frame to crop and XML?
Back in Premiere for the final export, the editor connects the xml with the original file, on a timeline of 2048x1080, adds credits and such, and then export.
Is it a correct workflow?