I think those 7-strings are cool if you are gonna use it from the 1st fret on your low B-string till a 6 step bend on the 24th fret of you high E-strings. hehe
Thats what those things are for, not to playback Korn or Limp Bizkit.

I play a Ibanez RG270 , Jackson PS3T and a Admira nylon string.