Thanking you in anticipation: use in the context

I have some doubts about using the expression 'thanking you in anticipation' in letters.

For instance, is it possible to say in the end of the letter:
Thanking you in anticipation,
John?

Should I use this expression instead of 'Best regards' ('Best wishes' etc.), or before that?

If you are waiting for a reply in a formal letter you can say "Thanking you in anticipation'"

Best regards/wishes is for an informal communication.

If you are asking something of someone, "Thank you in advance" sounds good.  I don't know how people speak in other lands, but in American English "Thanking you in anticipation" (точка!) does not sound natural.  You could, however, continue the sentence, as in the following examples:  "Thanking you in anticipation of your prompt response to this letter."  "Thanking you in anticipation of your courtesy and cooperation."   In my own business letters, I often use these variants:  "Thank you in advance for your anticipated prompt reply."  "Thank you in advance for your anticipated prompt attention to this matter."  "Thank you in advance for your anticipated courtesy and cooperation."  

After thanking the person, close the letter with a formula such as:

Sincerely,  //  Sincerely yours,  //  Yours sincerely // Yours truly,  // Very truly yours,   [all businesslike and formal]

or

Best regards, // Best wishes,   [informal]