Asymetric station configs and shuttle

The ISS was lucky in that the shuttles were grounded while the station
was more or less in a symetrical configuration. However, from now on,
station assembly will involve more asymetric configurations with the
truss extenting each direction.

If a shuttle were to have damage requiring the other shuttle to come to
the rescue, would the rescue shuttle bring up the module that would make
the station symetrical ? (or bring back the module that made the station asymetric)


What is the closest delay between a shuttle landing and the next one
launching ? Would NASA plan to have port and standboard peices launched
"simultaneously" (eg: both shuttles on pad being outfitted, with the
second shuttle launching the day after the first one has landed)

This would ensure that not only would there be a rescue shuttle ready,
but also that the module to make station symetrical again would be
launched as part of the rescue mission.

Considering that should one shuttle fail, it would, in practice, be the
end of the shuttle, it seems to be that ensuring the station is left in
a symetrical config would be important.


Shjould the shuttle be permanently grounded leaving the station
asymetrical, would the SSRMS be used to disconnect the truss module and
ditch it (or somehow attach it lengthwise on the spine of the station)
to make the station symetrical again ?

Or would an asymetric station not be such a big issue for long term
orbit keeping (once ATV flies, I assume there will be plenty of fuel to
compensate for asymetric station ?)