John Phillips wrote about regulation problems And asked for comments.

Normally, the stroke of a piano is not changing, since it's a fixed
distance.  The stroke is factory-defined, and does not change by
itself.  Therefore there is no need to change anything.  And a stroke
of slightly over two inches is quite normal.

Even if the hammers are sanded, correction is usually not needed.  Some
re-regulation however has to be done in such a case.  It is not good to
play around with the hammer rail.  That causes problems, as obviously
has been experienced.  My advice would be to bring back the hammer rail
into its original position.

And, since it's an old piano, it's almost unavoidable that some felt
and leather in the mechanism will have to be replaced.  Maybe even the
hammers!  The hammer butt buckskin may need attention, especially in a
dry climate, as may the polish of the tip of the hammer butt.  All this
probably requires the skill of a piano technician, who also will be
able to regulate the mechanism by the book.  Please keep in mind that
not every tuner is a skilled technician, and the reverse.

Jan Kijlstra