Of course, do remember that because TEI says an attribute value is space-separated tokens
does not mean that people do not use it as if were to be treated as a unit.

thus some people write

   <foo rend="small caps">

which, by the letter of the law, ought to be treated as "small" rendering
and also "caps" rendering, but, y'know….

There is some controversy here over whether 
    rend="a b c"
    rend="b c a"
can be treated as unordered sequences, and thus
be identical. I am fairly firmly of the opinion they
they _should_ be treated as unordered;
I am sure others will dismiss my theology.

Sebastian