I have to say I'm not a fan of the Avid roundtrip at the moment.
Using FCPs workflow I typically..
1. Get an XML.
2. Grade entire image in Resolve.
3. Send back XML to FCP (2k or 4k files).. and then any scaling information/flips/flops are reapplied.
1. Get AAF or EDL.
2. Grade entire Image.
3. Can't render DNXhD at 2k or 4k so... you have to do the scaling in DaVinci..(and in this case, there are hundreds of repos) and the scaling doesn't carry over.
Does anyone have a better workflow? For some reason the AAFs were not working and did not contain the scaling information.