Simultaneous contrast (from local edges) and assimilation (from remote edges) induced into physically identical grey rings.

I made two attempts to adjust the intensity of the ring not the right to match the appearance of the ring on the left.

Both increasing and decreasing the intensity of the right ring leads to poorer matches to my eye/brain.

Which of the three right rings matches best for you? And how good is the match on a scale of 1-10, 10 being "identical" and 1 being "as different as black and white"?