There are several variations of the Aeolian system Andy Hood describes,
listed here in chronological order:

1. Tracker ears tubed to valve block containing adjustable valves
identical to Theme primary valves.

2. Tracker ears tubed to valve block containing button valves.

3. As above, but tracker ears tubed through cutout block, disabling
them during reroll.

4. Tracker ears tubed through cutout block directly to tracker
pneumatic with valve block omitted.  In this instance the supply tube
goes to the tracking pneumatic instead of to the (absent!) valve block.

5. Tracker ears in bar with adjusting screws.  The roll wanders
wherever it pleases with the tracker bar following it.

Information explaining the fourth and commonest type of system may
be found on page 20 of the 1925 Duo-Art Service Manual reprint, and
includes an illustration.

Tracker ears are normally adjusted 11.25 inches apart plus a very few
thousandths. However, these systems do not compensate for variations in
paper width, so some further seasonal adjustment is usually necessary.

Humidity levels at the factory, as well as edge trimmer settings on
perforator at the time of manufacture will also affect paper width.
Ideally, no roll should lift both tracker ears simultaneously, even
if it means poorer alignment on narrower or age-shrunken rolls.

The earlier systems are often found upgraded with the addition of
a reroll cutout block.

Jeffrey R. Wood