Hello Terry, You're right about the 4/0 pins- probably installed some time ago, but not likely quite 200 years ago. I've seen some squares that sure look that old but have just been abused since 1900 when techs decided they didn't or wouldn't work on them anymore. I'd use 2/0 pins in your new plugs, since 2/0 gives a good feel. Most (all?) squares that I've seen have no plate bushings, and some had 2/0 pins, some had 1/0 and others were much smaller. Most older pianos had oblong head pins. I wouldn't worry much about plate thickness, just get the coils down nicely to achieve a good slope, and your work will be so much of an improvement over what was there previous. You're a brave man to tackle a large project on a square. Best of luck. Ralph Thorn a Canadian square guy
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