I didn’t know there was an Italian company. I only saw wire strings on their site. I wonder if they manufacture or only distribute. Given that they primarily do guitar strings, I might think that they are distributing D’Addario strings. Do you happen to know any details about them?
The ‘silk’ in the wire strings I have tested by holding to a match (I think they were Bow and Salopian) was something artificial- probably polyfilament nylon.
I live in steamy Florida and have been considering Aquila Nygut for a classical guitar, a nylon-strung minstrel banjo (fretless and tuned a fourth lower than the modern banjo) and–maybe!–a harp.
What I hear from banjo-playing friends: the Nylguts take their own sweet time about stretching out, but once they have done so, the majority like them very much. (A few prefer nylon classical guitar strings.)
I am a little reluctant to invest in a whole set of Nylguts for a 33-string harp, but if they really resist humidity and have a better tone than nylon–!