I need to set up the lightest possible workflow, to give my images (Sony A7III) to my collaborator who retouches my images, through the internet, and get them back as quickly as possible.
I was thinking of giving it in DNG, which is lighter than the RAW of the A7III, then repatriating the XMP containing the editing information. But Lightroom does not allow this. 😞 And fetching the DNG itself is way too long on a small internet connection.
For "Lightness" in a collaborative workflow sharing an 'Exported' Catalog is the easiest.
When you [Export as a Catalog] you get a Catalog to share accompanied by Proxy 'Smart Previews' (which are actually small DNG files 2560px long edge). You do not have to supply DNGs (either full-size or compressed) or Original files, or XMPs.
You do not need to create the Smart Previews separately- the [Export as a Catalog] does that automatically!
There are limitations- The Editor cannot create derivatives (eg. in Photoshop). Sharpening and Noise Reduction do not work well with the Smart Previews.