Horros,,,
The Cool back seats are comfy to many. Your Cervical Injury would IMO suffer more on any DF bike.
I base this opinion of my un Injured Neck hurting like hell on any DF bike.
In your case I would go to great lengths to Try and find bents to 'RENT' for a day ride.
Again the BROL forum I mentioned in my post #8, those people are very knowledgeable in this area and they can tell
you of many dealers all over who do long test rides on various models...
There are two shops In central Florida that rent bents,
both located right on different paved MUP's longer than 40 miles each..
http://www.hamptonsedge.com/index.html
http://bicycleoutfitters.net/
Diamond Framed bikes are pretty much all the same,
with seat and bar placement adjustments of only Inches this way or that..
Not So with bents, Good Test rides are far more Important.
I learned I would never want my feet above my hips on a two wheeled bent,
And this did not apply at all on a trike, odd I know.