At a King Crimson show, many years back (2003), I got to ask Robert Fripp how he was running his Guitar synth rig, and he was kind enough to direct me to his Guitar tech, John Sinks, who took me through the signal chain. FWIW, I went out and bought a Roland US-20 Unit Selector the next day, as that was the box that allowed Fripp to drive two GR units from one Guitar.
Just the other day, I saw a post on FB, where DGM had uploaded that show, including the Q&A at the end, as a download. At the very beginning of the Q&A, you'll hear Trey Gunn making fun of a fan who appears so "earnest" that maybe they shouldn't call on him? I was that fan, and they were kind enough to address my question, which you can hear along with Robert Fripp's reply. The whole show is available as a download, here - King Crimson, Birchmere Show, 2003
Robert Fripp also gives a brief burst of the solo from "Fracture" during the Q&A, which is worth hearing on its own.