[GraemeJ]

In your case it is not global settings that inadvertently were copied to the target device, but the fact that every song has the actual text display settings included in its individual metadata.

You can manually adjust one song to the right settings, and then apply this setting to all songs (there's a button for that).
But you would need to repeat this every time new songs are imported.

I don't know if this can be addressed with a simple "scale everything by ..." since it involves the subtilities of line and page breaking.

It's no big deal for me, but I can see how it might be a real problem for someone who is running a 'master' tablet for a number of people - all using tablets of different screen sizes.  It's simply too much to expect this additional input from each user and it would be interesting to get Mike's input on the possibility of scaling, dependent on screen size.  I suspect this is not something that would be easy to achieve.

NB:  As a simple solution I just converted the few files concerned to PDF - my problem solved, although I appreciate this would not be a good solution for many users.