\context for named Staff

[Jonathan Wilkes]

Hello again,
     I'm trying to resize one staff in a flute/piano duet, and I can't 
figure out the "right" way to do it.  Here's the format I tried:

\layout {
  \context { \Staff = "staffFlute"
    % stuff to resize this particular staff
  }
}

But I guess it's not possible to refer to a specific instance of a Staff 
in the layout block (at least I couldn't find any reference to doing this). 
If this is true, then how do you do staff size changes- like making the 
flute staff smaller for the piano score- without doing everything manually 
for each score/part?

-Jonathan