ps-avg-char-width
ps-avg-char-width is a compiled Lisp function in `ps-print.el
'.
(ps-avg-char-width FONT-SYM)
The average width, in points, of a character, for generating PostScript.
This is the value that ps-print uses to determine the length,
x-dimension, of the text it has printed, and thus affects the point at
which long lines wrap around.