[The Deuce]

The bottom B can be acheived that way. I'm only speculating, as all my guitars are 6 strings. That being said, you can purchase custom sting gauges at any good music store. If you get one thicker than your bass E, it would be easier to get the correct tension and be at that note.

To convert 7-6, I would play the notes 5 frets lower on the E, or play all 6 dropped, and play the high e up 5. Not too into Korn, so I'm not all that much help.