help with custom markup command?

[Monk Panteleimon]

Hello. 
I have been ambitiously reading the section on "programmer interfaces" and
the scheme tutorial in an attempt to make a special markup command. I'm not
getting very far, and I thought someone more clever and experienced might do
better. I also thought someone clever and experienced might quite
understandably say "that will be fifty dollars, please," but anyway it's
worth a shot.

Here is what I am trying to do:
This is a bit of code that I use in a \book block, but outside of a score.

\markup \pad-markup #3 \large{ \with-color #(x11-color 'firebrick) \italic {
\hspace #9 Deacon:} \override #'(line-width . 60) \justify{ What the deacon
says. } }

I want to condense this into a command so that {what the deacon says}
constitutes the argument-in-question, whereas the rest of the formatting and
the {deacon} argument remain the same. \markup \deacon{what the deacon says}
would be fine. 
Just plain \deacon{what the deacon says} would be even better. In fact it
would be splendid, if only I could figure out where and what and how
everything goes into the #(define ... scheme. Then I could alter that
definition for use with {what everyone else who isn't singing says}.
\rubric{some rubrics} etc. etc.
 
Right now I can't figure out where line-width and justification (both
important) should fit into the scheme demonstrated in the
#(define-markup-command chapter, nor am I certain that it wouldn't be better
to define it as its own kind of command, like #(define deacon( markup #:
etc... rather than something added to \markup.

I know that there is LaTex & lilypond-book, but my attempts with that have
been less than encouraging and ultimately harder than just using the \markup
commands in lilypond.

Thank you very much.
 
Monk Panteleimon