lg - the answers are pretty simple. The bass isn't wired for stereo in the first place, I just wasn't interested in going that route. And I don't use any effects. The SF-2 is actually my preamp.
My comment about using only one channel of the SF-2 was only to indicate that I'm finding I don't generally need the other, since the bass itself is so flexible. I do actually play with the second filter once in a while, just not very often. My current setup routes one channel of the SF-2 (the one I do use) to the ELF, so I play with the lows there, while the other channel runs full range to the other cabinet. For that, I generally find I can get what I want straight from the instrument controls. Plus, I already need two amp channels because of the ELF, so end to end stereo starts getting really messy (and expensive) beyond that.
For me, it was a carefully considered compromise between flexibility and simplicity. Certainly some of the things you've done are more flexible, but I don't seem to need all that (and this is already pretty complicated). I tend to be interested in a more narrow range of subtle tonal differences (for example, Ray Brown versus Miroslav Vitous?), and find I can do that pretty easily.
The real treat for me is that I always have the option of mixing the full range signals, with a filtered signal of my choice. You can also do that with an SF-2... but only if you don't use the filter(s) on the instrument. Once you start rolling off with the standard instrument filters, you can't really get that stuff back.
But while my focus is fairly narrow for now, I will undoubtedly explore further, there's a lot I haven't even touched on yet :-)
