Update: I checked the red clutch/coil lead in "failed" mode & I still had battery voltage which proves my relay is fine. I then forced the clutch against the rotating pressure plate (exciting - I recommend a thin wooden stick/pole - less sparks than metal) & lo & behold, it engaged. The gap is out of spec - not by a huge amount but it is bigger than the outside tolerance. I guess that over time the natural progression is for everything to wear & loosen to a wider gap.
So, it seems clear I need to pull the clutch & remove some shims. I've never messed with a compressor clutch & there is precious little clearance from the end of the clutch to the inner fender - maybe 3/4". I'm not sure what I'm getting into here. I don't think there is enough clearance without pulling the compressor & then I'm not sure you could do it without evacuating the system? Can you do this with the compressor in place or must it be removed? I'm wondering if I might be better off to take it to a reliable mechanic & have them do this. I wouldn't expect there to be too much to it for them....maybe 1 hour labor or something like that? Any opinions or experience on this? Thanks again.