I finished some other projects on the car yesterday, and repositioned it so that I can now work on the engine. Before I unplugged the battery, I plugged in the Durometric again and this time just data logged as I rev'd the engine from idle up to at least 6000 RPM. That clarified the failure mode...
(I neglected to log the engine revs, but you can see the issue.) The bank 2 camshaft would pop right up to the advanced setting at 2500 RPM, but the bank 1 camshaft seems pretty lazy. Given enough time, it will get there, but it's significantly slower than bank 2. You can also see that when I let the engine revs fall, that bank 2 would jump to the advanced setting on the way down at 5500 RPM, and drop again at 2500 RPM, while bank 1 would barely get started. So it looks like it's definitely the actuator rather than the solenoid since bank 1's actuator is definitely getting the message, but it's just slow to respond.
Alas, the actuator and solenoid are replaced as a set. Why is this a problem? I just bought a solenoid, and now I had to buy an acuator+solenoid set. I'll see if I can return the unopened solenoid.
In other news, I cut open the oil filter from the last time that I changed the oil in the springtime, and found a couple (2, maybe 3) of these in the filter.
I drained the oil from the car yesterday and changed the filter again, but I haven't had a chance to open it. I also pulled a sample to have lab tested. I'll post what I find in the filter this time around in a couple of days.
Right now the plan is to replace intake chain, ramps and actuator subassembly on the bank 1 side, and the intake chain and ramps on the bank 2 side.