Sorry, I have to say that I've had no look onto the plans of that
home built organ.  Are the 20-note rolls any different to normal
20-note rolls?!?

That would be quite unusual, as there is quite a lot of music for
standard 20-note roll organs.  Melvyn Wright is not the only one
to provide these, though.  (We had a list in one of the MMD's.)

greetings by(e) InK -- Ingmar Krause
ERlanger drehORGEL-Trio, Familie Krause, erorgelt@erlangen.franken.de