Hi @rapple,
just saw this post. It seems like we have a similar needs for a workflow, see the other topic I started.
Currently I am trying an approach where I don’t sync the database at all, but only the images and sidecar files and doing a somehow automatic discovery of new added images with help of a lua script. The new images could either come from another PC running darktable or just added without any knowledge of darktable e.g. when a smartphone uploads to a filmroll folder.
I guess synchronizing the database between multiple PCs only works if all PCs have exactly the same images and the pathes are the same.