I think the current wording about line length makes it too easy to adopt 99 instead of 79.  I propose to go back to 79 only, and add this before the paragraph starting with "The preferred way of wrapping long lines ..."

"""
Some teams strongly prefer a longer line length.  For code maintained exclusively or primarily by a team that can reach agreement on this issue, it is okay to increase the line nominal line length from 80 to 100 characters (effectively increasing the maximum length to 99 characters), provided that comments and docstrings are still wrapped at 72 characters.
"""