Ian, I think since you have two pouches available to control the
shut-off switch, you should use them both.  Why not tube the reroll
hole in the tracker bar, 8T, through the treble fast crescendo cut-out,
5T, and on to the switch.  Then tube the second pouch to the spoon
valve.

This set up will allow all other functions to be normal.  You will
have motor shut off at the end of the roll and also at the end of
reroll.  If the fast crescendo cut-off operates correctly, the tracker
hole 8T will not be able to fire the motor off switch during reroll.
As an aside, it appears that perhaps your motor shut-off switch is
a bit sensitive.  Perhaps it has no bleed or one that is clogged.

The cut-off function to the fast crescendo is absolutely redundant,
and can be eliminated with no change to that system's operation.

Bob Taylor