It seems there is a solution and it's largely NOT what has been considered in this forum.
The dealer hooked it up and communicated with Hans und Fritz, and as posted above, the GS-911 returned constant fuel pressure readings of about 2700 (millibars? kPa? psi? no one says) despite changing rpm. However the actual measured pressure was MUCH higher, causing overfueling.
Apparently the fuel pressure sensor on the fuel rail was kaput. Sensor replacement requires considerable work, so I authorized the work. It'll cost about USD$1000. Despite the sensor being used in a handful of bikes since 2004, it isn't in stock, will take some 3-5 days to come in and should be installed in a day. So, the bike will be at the dealer for about a week.
Close it out: I'm disappointed in the advice given on this thread, in accordance with which I spent some $800 for new coils, plugs and 02 sensor, and vacuum fitting for coolant filling, which purchases that only enriched the vendors. Now another grand for dealer work. The GS-911 might have pinpointed the problem if only I had baseline data to compare to, but no one could, or has yet, come up with such data on the real-time functions reported. What (expletive deleted) good is a measurement without a baseline to compare it to? We're not mechanical mind readers nor do we converse daily with the factory. I get that a modern machine is expected to be complex but most of this bike goes back almost 10 years. Where's the info? I don't hope or expect it will appear here. At best, I got free advice and it was worth exactly that.