The map shows Jerusalem as about 2-3 miles wide by 5 miles north-south. I don't know how that adds up to 1 square mile in your book... and 1 square mile certainly doesn't allow for the large population of Jerusalem described by Tacitus and Josephus, et al.
Of the Seven Mountains, two out of the three you referenced were specifically identified as "Mounts"; and as noted, Psalm 125:2 establishes that God considers the Mountains of Jerusalem to be, in the aggregate, "Mountains". Hence, if Revelation 17:9 refers to the geographic position of the City Babylon, the "Seven Mountains".
On the other hand, rereading it over and over again, I can't accept that they Babylon and the Beast are seperate cities. The beasts heads are 7 hills; she sits on the hills. She doesn't sit on the beast, which sits on the hills. But to say that the scarlet beast is Jerusalem sounds, well, satanic. Jerusalem was corrupted, but the beast itself is evil (hence, the Bishop of Rome serves from outside it!).
The Beast is Rome and the Seven Caesars (and, presumably, the Ten Senatorial provinces with the Imperium).
The Whore who rides upon the Beast, OTOH, is THE Great City (Revelation 11:8) who is guilty of the murder of the Saints and, specifically, guilty of the murder of the Prophets. Now where in Scripture, anywhere in Scripture, is ROME said to be guilty of the blood of the Prophets?? Name that Scripture!!
What city does God judge guilty of the blood of the Prophets, dangus? "For it cannot be that a prophet perish out of Jerusalem" (Luke 13:33).
On reflection, I can see the ten horns turning on the woman corresponding to the beast itself turning on the woman, if not for the fact that the horns are kings. I can't grasp how *ten* kings attack Jerusalem, which is why I never bought it earlier. Nor can I picture the kings of the earth mourning her, nor did she deceive the nations with her sorceries, nor were her merchants the great men of Earth.
At the end of the day, Jerusalem is THE Great City (remember, you have never cited any textual reason why Revelation 16:19 is speaking of a different "THE Great City" than the one already established in Revelation 11:8), who deceived the nations into attacking the Church of Christ, the Old Covenant bride of the Greatest King who had made herself a Babylonian-clad Whore, who was guilty of the blood of the Saints and the Prophets.