How hard do you play? I really think the free option of adjusting your style to a lighter touch will make a bigger difference than any bridge/nut/string anchoring. Working with your compressor to balance the limiting compression, threshold and release can really make a huge difference.
I have a lot of basses, all sorts of bridge/tailpieces and never run out of note... before I run out of song. Songs that ring out at the end, I always find myself having to turn down the volume on my basses rather than letting my note keep going.... I'd be going on many seconds longer than the guitar players.. let alone drum/cymbals. It could be the music style etc needs way longer notes than I run into.. But sustain is one thing I've never been lacking. What kind of songs are you playing where you run out of sustain?
I have a lot of basses, all sorts of bridge/tailpieces and never run out of note... before I run out of song. Songs that ring out at the end, I always find myself having to turn down the volume on my basses rather than letting my note keep going.... I'd be going on many seconds longer than the guitar players.. let alone drum/cymbals. It could be the music style etc needs way longer notes than I run into.. But sustain is one thing I've never been lacking. What kind of songs are you playing where you run out of sustain?