Thanks, everyone.
Unfortunately, I *definitely* need the cut-out. I always have, even with a hybrid and a mountain bike. Because my back is all fused, I can't take pressure off the front of my pelvis when I ride (it takes the brunt of my weight, rather than my sits bones), so I need the gap in the saddle to take all that pressure off for me.
Interesting insight into the "high sides" of the Jett--that's exactly what I have been feeling. If I can find a "shallower" saddle, which also has a cut-out, that might just do the trick.
And the shorts--I'll try a small instead (despite my fear of sausage). Those darn Sugoi are made of just the softest, most invisible-feeling fabric ever, so if the small one has a chamois that does not shift/rub on me, I'll be ecstatic.
This weekend will be weekend number 3 of morning-til-night experimentation and *cha-ching* credit card charges at the LBS! Does it ever end?
There's only one thing better than spending a day on my bike: Spending a day on my bike in good company.