Spacing Priority

[Stephan Elliot Perez]

Hello,
        I am trying to change the spacing priority of either \markup obects or pedal markings (\sustainOn and \sustainOff ) so that the latter will be displayed closer to the staff than the former.  I have tried lowering the priority number of \markup with

 \override TextScript #'outside-staff-priority = #500

as well as raising that of the pedal markings with

\override  Staff.SostenutoPedal #'outside-staff-priority = #300

but neither works.  What am I missing?

Many thanks,
Stephan