In addition to this subject I would like to comment that in my
opinion a good (the best?) way to transcribe a piano roll to a good
MIDI-file is to play the piano roll on an excellent restored player
piano or reproducer and record the MIDI-file 'from the keys' with an
optical device like the PNOscan MIDI record strip (QRS) or something
similar.

For reproducing rolls you then will record the music played as it
was meant to be played with the player mechanism in it best way.
And for normal piano rolls you can record the notes with the expression
of a talented pedaller.  On an optimally regulated MIDI-piano these
recordings should sound as good as the original recordings on paper.

Waldemar Raad, Holland