It gets harder when there are other kingdoms in the equation. I realise of course that Sardinia was ALWAYS there as a kingdom, but until after Vienna, Savoy's main status was a dukedom, that happened to have the kingship of Sardinia attached. Whilst in essence Piedmont-Sardinia was still this (Piedmont not being a kingdom) after Vienna, its ruler became increasingly seen as the major king of the North. And after Vienna, the Viceroyalties of Lombardy and Venetia emphasised formal Habsburg power over these domains as sub-kingdoms of the new Austrian Empire.
Best Regards
Grey Wolf