The King Crimson (Frame by Frame) 4 cd-box set came with a HUGE booklet that was basically Fripp's artistic manifesto at the time. It's crazy.
I'm not sure "cleverness" is really the distinction between the two. Afterall, Belew is primarily noted for his "cleverness" in getting animal sounds and assorted squonk out of the guitar. I'd say "cleverness" is actually the trait the two have in common. But Fripp is a total eccentric and Belew's pretty down-to-earth.
I think Belew is an extremely clever player, yes. But with Fripp it's more like the cleverness is the whole point, that's the distinction. That's really the only thing I like about him, how clever he is. I can see he loves the endless mathematical possibilities of the six strings, 22 frets and applicable time signatures. I'm just not sure he particularly likes music.