When Dino was in FF, it was an EMG 707. Now that Christian is the guitar player, its the EMG 81-7.
I bet any hotter-than-hell Duncan would get you pretty close, just make sure to dial in a mid & treble heavy tone with rediculous amounts of gain.
Another key factor in Dino's tone (I can't say this about Christian) is really light guage strings. Dino used 10-50 tuned down 1 whole step.