So I'm the guy who wrote the review of the Bois ligature that Differencetone referred to in one of his posts earlier. The company eventually did respond to my e-mail and was nice enough to send me two replacement caps for free. One of the caps they sent was the very same clarinet cap that came with the ligature when I first bought it, and the other is a saxophone cap that actually fits my soprano mouthpiece.
The ligature itself fits very well on my Metalite & Graftonite mouthpieces and doesn't go down too far. I noticed recently though that the fit of the ligature greatly depends on the thickness of the reed. I use Rico Plasticovers on all my instruments and found one that was a little thicker than some others, causing me to have to use more force when putting the ligature on (I was almost wondering if I would even be able to use that particular reed with that lig). Also, while the ligature is designed for a rubber soprano sax mouthpiece, it also fits nicely on my metal tenor Berg Larsen.
I also ordered a Bois ligature for my clarinet and, just like with Differencetone, it also seems a little big for the mouthpiece, making the ligature hold the reed closer to the bottom end than I would like. Because of this, tones I produce on the instrument don't come out as cleanly, especially in the lower register. When I apply a little pressure with my thumb on the reed (closer to the middle), the tones I get are more what I would expect. Likewise, I don't have any problem when I use a Rovner or standard metal ligature. I tried the clarinet ligature on my alto sax Graftonite mouthpiece and it fits perfectly. I was hoping it would also fit my metal tenor Otto Link, but it's a little big.
Overall, I like the ligature but will only use it on my saxes. I will use a Rovner or Vandoren M/O ligature on clarinet.