You don't have to take the crank arms off to adjust the eccentric- that is misinformation. Or at least I never have during my time owning a Cannondale tandem over the past 15 years.
I always release the wedge by loosening the bolt a bit, putting a punch in the bolt head and giving it a firm rap with a hammer (the punch, not the bolt). This has also worked really well for the past 15 years with no evident ill effects.
I recently bought a Ventana off-road tandem, and have had the opportunity to see the Bushnell eccentric up close- it is a fine piece of work, and I may buy one to put in the Cannondale since it works so well and is completely self-releasing.