I'm in a similar boat, but I use a different saddle (Adamo). I'm not sure that it's the saddle that has caused my issue. I know I've had sciatic troubles for a while now (driving long distances has been an issue prior to me riding the Adamo).
My issue showed up first as chronic tightness in the left low back. This fall I started getting hamstring pain on the right side. Nothing major, just wouldn't go away. Driving was almost the worst thing for it.
I started rolling my low back on a TP roller and that has helped a lot, but hasn't solved the issue. In fact, after a couple days of taking it easy with S,B,R the pain came back as bad as ever. I have no idea why.
I did see a chiro for a while and he did nothing. I'm now going to try going to a different guy as I don't seem to be having much luck solving the issue myself.
While my situation got really bad this past fall, I know I've had chronic tightness in my left low back for at least a year. As it never bothered me I'm not really sure when it started. I only made a mental note of it a year ago as I was dealing with hip/IT pain on the left side. I was told that the issue with that was weak gluts.
I do try to do lots of stretching and strength exercises as well as self-massage. Keep us posted if you get it sorted out.
Edited to add...
I found this link on Piriformis Syndrome very interesting and may explain a lot of what I have been experiencing. Does any of that sound like what might be happening with you? http://en.wikipedia.org/.../Piriformis_syndrome