Custom grid ? how do I ...

[K4GAP]

I want to have three vertical sections on my Articles page. I'm using the grid below ...

<grids>
    <grid name="Mine" auxheader="0" auxfooter="0" addcolumn="1" addcolumnsnap="1" addcolumnsize="4" columns="4"><![CDATA[<div id="doc3" class="yui-tvb-r4">
    <div id="bd">
        <div id="yui-main">
            <div class="yui-b">
                <div class="yui-gd">
                    <div class="yui-u first yui-panel">
                        <ul class="list_no_decoration widget_list" id="widgetlist_column1">$column[1]</ul>
                    </div>
                    <div class="yui-u yui-panel">
                        <ul class="list_no_decoration widget_list" id="widgetlist_column2">$column[2]</ul>
                    </div>
                </div>
            </div>
        </div>
        <div class="yui-b yui-sidebar">
            <ul class="list_no_decoration widget_list" id="widgetlist_column3">$column[3]</ul>
        </div>
    </div>
</div>
]]></grid>
</grids>

Which results in this ....



What I want and need is for the left column to be the same width (300px) as the right side sidebar that I have set at 300px.

Using the code example above, what changes in it have to be made to accomplish what I want?