Thanks for the thoughts. With strong documentation and 30k service performed 50 miles ago, I know all elements you mentioned to be less than 12k old - plugs, of course, brand new.
I had the vehicle broken down and diagnosed again today.
On the scope I could see #2 not contributing, bottoming out at 30%. But it had good compression. So the tech decided we had a fuel problem rather than an engine problem. He was hoping for an injector problem (though injector abt 11k miles old). He swapped #1, #2 and found #2 still crapping out. So by default, that left fuel distributor. That too is 11k miles old, $1k Bosch rebuilt.
Bad news: 12 month warranty at 21 months
Good news: 12k mile warranty at 11k miles
Really Bad news: Whichever comes first
Great news (resolving original issue of the post): When the parts were reassembled today, the resulting idle was much calmer than when I brought it in this morning. Mission accomplished, I guess.
I'll have to see how well the shop stands behind its work (ie. what kind of deal we can work for the fuel dist... if I get that, the car should purr).