Yo!
I dont own my own fretless (yet), but i will as soon as i've sold my guitar. In the meantime (there has been 2 years now! man....), i've been borrowing my uncle's MIA fretless.
These are the strings i've tried on it, and my opinion:
Rotosound 66 PSD's: Great tone, very much overtones and brigthness when played "open". I found it hard to get a mellow, sweet, singing tone, but that may have come from the heavy ash body in teh bass. More "meow" than "mwah" though, and they was VERY buzzy when you lost the control of them. If its good enough for Jaco.....
Rotosound Tru Bass Nylons: Whoa....cool strings. They feel very soft and rubbery, has a very low tension and a "rubbery" tone. Very fat tone, and it let me imitate an uprigth when playing near the neck. Its "fingerboard" clacking were very musical, and gave it a really fat mwaaah.
WHAT? Only two packs of strings? That means i've been using the same strings for a year now?!
Time to change them i guess....maybe i'll try T-I Jazz Flats next?
Cheers!
-Erlend