So how did I do the adjustment?
After noticing this issue and thinking (but really not sure) it might be the root cause of the excessive camber problem, I tried levering things with a pry bar. Maybe I could have tried harder at that, but it got nowhere.
So I went full overkill and (I still don't know how much of this is all actually necessary, but it was very easy and did not take a lot of force to move things):
Compressed the suspension spring. If I had airbags, this would be very easy. But I had to use my little old spring compressors. I jacked the suspension to fully compress the spring, fit the compressors in there (barely fit, and these are very small compressors), and jacked down the suspension, moving most of the supporting force back to the jack stand. So the spring was still in place, but was no longer stressing the whole suspension. This made things much easier to move.
^^^ But I'm not sure how much that step is necessary. It was convenient for me, and I thought it would help so I did it. If you have air bags, deflate them. If you have spring, but no compressors, I'd skip that step - you might need to pull harder on the winch, but I expect things would still move.
Removed the eccentric nut and washer, so I could see how the bolt moved. "After" photo in a following post.
Used a winch / come-along between the left and right shock supports, with C-clamps as interfaces to pull the left and right suspension towards eachother.
With things freed up due to the spring pressure being removed, it moved very easily, with hardly any force needed. I moved it so the rear/nut side of the bolt could be seen up against the end of travel limit (shown in photo in following post), then tightened things. I expect it moved a little while I did this, so that bolt is no longer at the limit shown by the photo.
Removed spring compressors, etc. Torqued that rear nut to 165 Nm, and measured camber at -1.4 degrees
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