On Metternich, one has to proceed carefully. A good place to start is:

Enno E. Kraehe. Metternich's German Policy. 2 Vols.

Henry Kissinger. A world restored : Metternich, Castlereagh, and the problems of peace, 1812-1822.

Kissinger considers Metternich his hero, so you need to keep in mind his bias. Also, one needs to keep in mind that Castlereagh, the British Foreign Secretary is a major player in all of this. Charles K. Webster's, 'The foreign policy of Castlereagh, 1812-1815, Britain and the reconstruction of Europe', is the best place to start.

-Alex