There is only 1 notice that is required when force placing insurance. It is to be given as soon as the borrower's policy expires. The MPPP has a series of 3 letters, but this is not required. They were only provided in the (now repealed) Mandatory Purchase of Flood Insurance Guidelines.
In the example you provide, you can notify prior to 3/1/17, but you must notify on 3/2/17. Again, only 1 letter and there's no specific format or requirements to be contained in the notification letter.