A nylon strung guitar, tuned down

[Steve Lunn]

Hi, My cousin sings and plays guitar, but because she used to be an opera singer she tunes standard tuning down quite a bit. The question is, could I design and build her a guitar that would allow this tuning without causing fret buzz and really slack strings, I hope this doesn't sound too silly as it is my first posting. By the way she sings a latin jazz style these days, many thanks,
Steve

[FRANK]

string length i had to correct you sorry