Turns out I'm blind and I didn't see nor find the "Calculate average album ratings" section on there when writing the above :/
On a third attempt, when looking for something else I did see it though..
Now, as for best-/recommended-usage... since I do not want the album rating to be written to file-metadata, what's my options here ?
Setting "Album Ratings are stored in: " to " "Null" " ?
And having
"Auto calculate Album Rating on start up" enabled ?
This seemed most appropriate for my case... but upon testing on a sub-section of files, and it scanning and reporting 'Album Rating 100% calculated' or somesuch, I fail to see where the album rating would sit, and how to display it (i.e. which view) and how to sort by it - any chance to do the 2 with an Album centric view when not storing the album-rating in metadata ? I though MB's virtual Tags could be a way out here, but I could not see the option in the field drop-down, only custom fields, which are in-file again.
Cheers.
c.