Hello!
We are proud to share with you a new plugin : Display configuration
Available on the store, for x86 HW and Volumio4 only.
A screenshot to have an idea…
google “x86 xrandr overscan correction”, this may show some ways of adding it to the plugin, but no guarantee. I suggest to test this first using ssh on @pauljwells installation.
Correct, x86 out-of-the-box has been configured as a generic setup, this plugin is extremely valuable to add machine-specific settings and does it in its own way. Everything you read about RPi and config.txt or userconfig.txt is not x86-related and therefore completely irrelevant.