Tricky layout problem

[prim0pyr0]

Have a tricky problem with my site:

I have removed the categories box from the main page, but now i want to reduce the margin/space it has left.
I can change the size through the admin>layout settings>Column Width - Left Boxes changing it from 150px to 100px looks good on the main page..
But, then the product pages/all pages with categories box displayed don't have enough space and get all messed up.
How do i change the main page to be less px than other pages?

Other query is how to stop categories box displaying in pages like checkout.

site is www.thruthelenz.co.nz , www.thruthelenz.co.nz/gallery for where categories box is displayed

[Website Rob]

Presuming you already have these settings:

Admin > Configuration > Layout
Column Left Status - Global 1
Column Right Status - Global 0


Admin > Tools > Layout Boxes Controller
- everything OFF except for Categories Sidebox


open - includes/templates/pgsnow/common/tpl_main_page.php

near the page top, around line #42 you will see this line:

if (in_array($current_page_base,explode(",",'list_pages_to_skip_all_right_sideboxes _on_here,separated_by_commas,and_no_spaces')) ) {
$flag_disable_right = true;
}

change it to read:

// if you want your Category Sidebox to show on your Shopping Cart page, remove the shopping_cart, part from the line below.
if (in_array($current_page_base,explode(",",'shopping_cart,checkout_shipping,checko ut_payment,checkout_confirmation,checkout_success')) ) {
$flag_disable_left = true;
}

if ($this_is_home_page) {
$flag_disable_left = true;
}

You should also correct your HTML Validation errors as you have many and some are serious.

http://validator.w3.org/ << a site you may want to Bookmark