It is really cool that Emby has the ability to support multiple versions of the same movie. It would be nice to have a setting on the client side to allow the user to set which version should be selected by default. This could be as simple a user-entered string, or it could be a list of detected strings to choose from. It could allow multiple entries and it would choose them in the order entered.
On the Kodi side, it would also be nice to get the "Choose the Best Version for Me" option that
I really don't think this particular request is the right answer to your issue. The multi-version feature is designed for multiple qualities of the same item as opposed to different cuts. While it can be used for different cuts, it has these types of limitations. Instead of continuing to try and satisfy both of those situations with the same feature, I really think we need a different way to handle multiple cuts because marking one of these as "default" then negates some of the functionality