I don't mind breaking the set apart. All inquiries I've had thus far though have been from people who were interested in having a same number collection. It does seem a shame to break the numbers apart.You would be better off selling the Black House and Desperation separately. You should get $275 to $325 each for them.
Most collectors are already going to have one or more of these books, so they are not going to buy a large collection like this. Parts of it yes. The whole thing no.