changing eg thickness of many lines at once

[Tom Yates <madlists teaparty net>]

i have a diagram containing a large number of lines, which i find (now i 
have access to an A3 printer) are much too thick.

i can select all the lines, either manually or select by type.  is there 
any way to change the thickness of all of them at once, or must i do each 
one individually?

i'm really sorry if this is a FAQ, but i can't find an answer elsewhere.


--

  Tom Yates  -  http://www.teaparty.net