Starwood Preferred Guest - Dealing with terrible restaurant service - who to write to?

Just drafting a letter for some service at dema (Westin DTW) that, well, simply put, isn't the "Best of Westin". (simply put: great food, but I never spoke to my waiter, or the restaurant manager)

Am planning to provide my feedback to help the hotel fix their issues, and am wondering who to write and cc to for my letter.

Was thinking

To: Restaurant manager
Cc: Hotel GM, William.

Anyone else?

Why didn't you address it with the restraurant manager at the moment it happened? What are you hoping to achieve from this letter?

Huh?!? I'm already lost and find myself unable to follow your intent. Did you not speak to your waiter or the mgr b/c they were inaccessible to you (i.e. the place was mega-busy and they had no time for you) -- or -- do you mean that you sat there politely and opted not to raise any concerns at that time to either of them?

FWIW, I would strongly recommend NOT cc:"ing" William on your communication to the hotel --- nothing's worse than getting a letter that has been cc:ed to half the free world.