Custom markup

[Sven Axelsson]

I want to create a simple text markup that should be placed
*at a fixed height* below the notes. I haven't figured out 
how yet - so many properties.

I have this now

tc = \markup { \column { "T" "C" } }

and using it like this

\relative c' { c4_\tc g'_\tc b_\tc }

which is OK, except for the mark shifting up and down a little
depending on the notes. How can I fix that?

And ideally I'd like the command to be c\tc and not c_\tc as
of now. Is that possible?

Thanks

-- 
Sven Axelsson