I would like to build my own busker organ with at least 31 notes
and four or five registers (about 100 pipes), since I will probably
never afford a Raffin (my dream machine) or a Hofbauer.  I've gone
through the MMD links and discussions there and have some questions.
Perforated roll operation would be okay, or MIDI operation; is there
any kit that uses both?

The John Smith "Topsy 3" looks like a possible choice, but in just
about all of the YouTube videos the instrument doesn't seem to be
synchronized very well, with some registers lagging.  Has anyone
tackled this issue and solved it?  Are there other kits or plans for
an advanced model?

Regarding tuning, does the most common 31-note scale center around
a limited number of keys such that a variety of meantone tuning can
be used to advantage?

Thanks,
Chris Kocsis