Shoot, I'd love to talk about this, but I'm working tonight (sort of a continuation of the weekend...), so I'll just throw out a suggestion or two.
As I understand it, you have a very clean, non-mwah sound on your fretless, and you'd like to get some of it back.
Since you already have the bridge way low (and apparently that works fine), I'd suggest straightening the neck a little. It seems to me that a nice fretless mwah comes from a very slight grazing of the string, along much of the vibrating length. (This is somehow different than fretted buzz, where you often hit a particular fret, or maybe several.) If you have too much relief in the neck, you won't get this.
So setup is probably the first thing, but technique matters too. If you use a *lot* of fretting finger pressure, hit the note dead on without sliding into it, with perfect intonation, all the time (well, in theory I suppose some people might...), you're less likely to mwah. Try sliding into it just a bit, maybe with a little less finger pressure. (Don't bother plucking harder, that gives you more of a slap than a buzz.)
As to strings, I have no experience with yours, and won't speculate as to their effect.
Back to work - good luck, let us know what you learn.
-Bob
