I like your system. Must sound very good. I have the Silversmith ribbons too. Excellent!
And I have the exact same problem. Also on the right.
Now that I think of it relative to your right leaning issue, I think I have the answer.
About 20-30% of my LPs the soundstage leans to the right and also seems to be right focused on everything. My left speaker is in a corner and the right speaker is open to the room. I too have no choice in my room.
All I can say is that I have learned to live with it. I have tried to turn down the gain on the right but that was problematic. Believe you have a balance control. Try it but you may have the same problems with the imbalance of volume,