The perfect minus

[Mark Summerfield]

Hi,

I'm typesetting a textbook using lout and I need a minus sign with the
following properties:
1) exactly the same width as a + sign;
2) exactly the same line thickness as a + sign's crossbar;
3) exactly aligned with the + sign's crossbar.

This macro is the nearest I've come to achieving this:

macro @minus {
    {white @Colour address@hidden @address@hidden|0.175fo -}}
} 

Is there a better way?

-- 
Mark.