I have backups of both stock and my tweaked GraphicsConfiguraion.xml file, now can I just drag my tweaked one across from my backup drive rather than having to edit all the parameters again after the latest patch? Or does it being a new patch mean it won't work?
The old file will work, unless major alterations have been made to the base during a patch, which is quite rare.
It's also easy to compare files with something like windiff or notepad++ to see what exactly has change and merge changes.
As others have stated, if possible, it's best to put adjustments in the override file.
Don't modify the GraphicsConfiguration.xml file.
Put only your changes in the GraphicsConfigurationOverride.xml file that's usually found here:
C:\Users\<username>\AppData\Local\Frontier Developments\Elite Dangerous\Options\Graphics
This file is not touched during an update.
It's worth noting that there are a handful of tweaks which will not function if placed in the override.
For example, you cannot add shadow frustums to the shadow profiles,
nor can you disable the prototype light balancing.
Edit: It's been possible to disable the prototype light balances via override for some time, as of this edit.