Thanks for your speedy reply, but unless I've missed something that section is purely about build configurations. This is fine, and the way I've configured my packages at the moment (by adding the compiler switches to each package tied to WIN32), but it makes no mention of how to add an option (be it compiler switches or additional libs) that will automatically be applied to all packages in the project without having to add it manually to each one.
If you would like to experiment with compiler options (e.g. for speed), then you should rather be interested in altering/adding the build method... (may I ask what compiler switches you need to specify?)
To add additional libs, simply add it to some of packages.