Hi steinwayguy!You're always telling me I'm f***ed up, but here's what I've heard...Everyone has told me that the g minor is the hardest, followed by the c minor. The rest of them are all very difficult, but the G Major is the easiest. As for the set being harder to pull off than the WTC.... come on, really.... what do you think, my friend?
All of Bach's organ works are more difficult than the WTC, except there's one Prelude and Fugue in Book I that's the hardest keyboard work Bach's ever written.