Four hours and a trip to the hardware store later - David has a new home office setup.
(triumphant music cue here)
Believe it or not - instructions from Crate and Barrel desks are WORSE than the ones with IKEA furniture. He had already warned me that it would be relationship strain to try and help him put it together - apparently the only time he can remember ever having a knock-down-drag-out fight with a boyfriend is over furniture construction. So I helped lift the boxes up into the living room - then slowly backed away - as he broke them out and put them together.
He's extremely happy with his choice.
This is a a huge step up from the desk arrangement he had before - which even he agreed was so bad we didn't take a "before" photo.