I use an Ibby TS-7 that's been modded into a TS808 (and has the equivalent to the AnalogMan "brown" mod) in front of my Triple, with the drive off, tone at about 9:00, and level to match. On channel 2, I'm *almost* in SLO-land - thick, creamy, and sweet. On channel three, it retains the vicious edge while tightening up the bottom slightly. I can also use it on cleans to get that "bit o'grit" sound, like a cranked Bassman.
Overall, I'm really happy with what it's done to the amp. I have it set up so it switches in and out via MIDI with the rest of my FX (G-Major in the loop), so that each individual patch has the OD on or off. Gives great flexibility for my cover band, too...