A bit more info:
Tracker bar holes are 1/8" wide, on a 3/16" pitch. Definitely not six to the inch. There are 61 note-playing holes, three large holes and one lonely hole on the far left which lacks a connector on the back. This is OK, because there are only 64 input nipples on the valve chest. (There are 65 valves, though, but one of them has been blanked off. Phew!)
The valve chest also has connectors for external pneumatics marked Sustain and Motor Off, which accounts for two of the large holes in the tracker. Which leaves the last for rewind. Motor start is electric via the coin box. So far so good.
61 notes is the same as Hupfeld's electric pianos of around 1902, according to Orde-Hume.
Vacuum is regulated only by a spill valve on the main reservoir.
There is another connector to main vacuum, also blanked off. Mandolin rail perhaps, with a separate valve plumbed into that spare hole on the tracker?
Rolls are 13 3/8" wide, more or less. Nothing that says 'Kessels', sadly. Some English, some German. Some anonymous, but titled in French.
The roll centre has a built in trip lever like the one on the take-up spool, in case the paper comes off altogether.
If there's a maker's name on the player, it's very well hidden!
Mark - please feel free to use anything you need, and don't be afraid to ask for more...