In his book 'how to play against 1.e4' McDonald says Neg5 attacking f7 is what scares Ft. Knox players the most. And gives this reason, "... black not only delays his kingside development for two moves whilst he puts the bishop on c6, but also because the bishop is moving away from the defense of the e6-square."
The Goldfinger Variation
(seemed an appropriate name)
1.e4 e6 2.d4 d5 3.Nc3/d2 dxe4 4.Nxe4 Bd7 5.Nf3 Bc6 6.Neg5 Bd6 (McDonald says this is best) 7.Nxf7 Kxf7 8.Ng5+ Ke8 (McDonald says here that White doesn't have enough for the piece. I'm not so sure about that.) 9.Nxe6
1) 9... Qh4 10.Bd3 Qf6 11.0-0 Ne7 12.Re1 h6 13.c4 Bd7 14.d5 Na6
2) 9... Qf6 10.Bc4 Qg6 11.Ng5 Nh6 12.0-0 Kd8 13.Bd3 Qf6 14.c4
3) 9... Qe7 10.Bc4 b5 11.Bb3 Qh4 12.Nxg7+ Kd7 13.Qd3 Qe4+ 14.Qxe4 Bxe4
4) 9... Qd7 10.Bc4 Bxg2 11.Rg1 Qc6 12.Qe2 Bf3 13.d5 Bxe2 14.dxc6 Bxc4 15.cxb7 Bd5 16.bxa8Q Bxa8 17.Rxg7
White seems to be doing well in all variations. Another consideration is the nature of play, the Ft. Knox is played for a reason and a wild melee with black having a long desperate defense isn't one of them!
On ICC I once played the Ft. Knox in a blitz game. My opponent (white) resigned after 9 moves and said, "Why play chess? Just take a sleeping pill!"
The Goldfinger Variation gives the white player an opportunity to make life miserable for a black player looking for a safe and solid position.