I understand you may be looking for an exegesis that fits within your existing view ('that 90% of the Book of Revelations is yet to be fulfilled'). However, I will be offering a more grammatical-historical approach.
The Roman Empire destroyed Jerusalem and its temple in 70 AD, an event Jews quickly began comparing to the destruction of Jerusalem and its temple by the historical Babylon in 587 BC. Other Jews contemporary to John specifically call Rome by the name 'Babylon' as a symbolic gesture.  Accordingly, most scholars understand the name 'Babylon' in the Revelation to be symbolic for the city of Rome. John further identifies Babylon as 'the great city' which is seated on 'seven mountains'. Again, most scholars see this as a deliberate reference to Rome's nickname as 'the city of the seven hills'. 
Revelation 18 is thus understood as a lament for the downfall of Rome (patterned after Ezekiel 26-28), particularly as this downfall is perceived by the very people who prospered by Rome's violence and wealth. These are the merchants John mentions.
The 'magic spell' (other translations say 'sorcery' or 'enchantments') is the word φαρμακεια (from which we get the word 'pharmacy'), which describes something involving drugs. It could be used for magic-based potions, poisons, or even medicine. Because John says this φαρμακεια is the manner by which Rome deceived the nations, he may be referring back to the 'wine of her sexual immorality', mentioned in Revelation 14.8 and 17.2ff. She has made the nations drunk on her wine, and led them in the persecution of God's people.
 1 Peter 5.13; 4 Ezra 3.1-2,28-31; 2 Baruch 10.1–3; 11.1; 67.7; Sibylline Oracles 5.180-201
 Cicero to Atticus 6.5; Georgics 2.534-535; Aeneid 6.781-783; Elegies 3.11.55-57; Tristia 5.69; Epigrams 4.64; Sibylline Oracles 2.19; 11.145-154; 13.61; 14.138