custom grids easy? , Very Confusing...

I have been trying for the last couple of days to customize the 960 grid by using a subtheme with no success.

I am trying to follow the following instructions , but i'm not sure how old the instructions are
and I think example 1. might have an error at step 7. It says to include stylesheets with alpha in the
title , when it previously said to replace "alpha" with yourtheme.

compare step 5. with step 7.

ex.1) Creating and Setting up a Custom Grid for Omega 3.x
http://groups.drupal.org/node/164684

ex.2)How to define my own 960 grid ?
http://drupal.org/node/1321098

ex.3)how to overwrite omega 960 grid margin?
http://drupal.stackexchange.com/questions/13561/how-to-overwrite-omega-9...

I have read fubhy's comment here
http://drupal.org/node/1174324

In Omega 3.x you can generate and include your own custom grids! This is quite easy and pretty straight forward but is not documented anywhere just yet.

Can someone please give simple instructions for using a custom grid in a subtheme.