Timechart Command to calculate totals for 7 days

I have a search that I'm using to populate some charts in a dashboard. The search is checking a log and charting the top 20 users who have used the most disk space in their home directories. It works great for a 24 hour period...However I can't seem to get it to work for longer periods such as 7 days or more.

What I'd like to do is that if you choose 7 days, it would display the top 20 users who were using the most space after pretty much calculating space usage for 7 days per user. You'd be able to see the user's space usage over a 7 day period. This would allow you to see when a spike may have occurred that caused a disk issue.

The search I have right now is :

host="ynfs1" sourcetype=userdiskusage earliest=-1d@d latest=-0d@d | rex field=_raw "(?<Space>[\d]+)\s*\/home\/(?<UserName>\S+)" max_match=1000 | search NOT UserName="shares" | table UserName Space | sort -Space | head 20

This search is used to create an area chart on a dashboard. I have a time range picker to change the time from 24 hours to 7 days, but when I do the results are not what I would like. Nothing happens for the most part. Here's my dashboard code:

    <view template="dashboard.html">
  <label>YNFS1 Space Usage</label>
  <module name="AccountBar" layoutPanel="navigationHeader"/>
  <module name="AppBar" layoutPanel="navigationHeader"/>

  <module name="Message" layoutPanel="messaging">
    <param name="filter">*</param>
    <param name="clearOnJobDispatch">False</param>
    <param name="maxSize">1</param>
  </module>

  <module name="TimeRangePicker" layoutPanel="panel_row1_col1">
    <param name="searchWhenChanged">True</param>
    <param name="default">Last 24 hours</param>
      <module name="HiddenSavedSearch" layoutPanel="panel_row2_col1" group="Space Usage by user over a given time" autoRun="True">
        <param name="savedSearch">Andrew ynfs1 search</param>
        <module name="HiddenChartFormatter">
          <param name="charting.chart">area</param>
          <param name="chart.stackMode">stacked</param>
          <param name="secondaryAxisTitle.text">Space</param>
          <module name="JobProgressIndicator"></module>
            <module name="FlashChart">
              <param name="width">100%</param>
              <param name="height">400px</param>
            </module>
          </module>
          <module name="ViewRedirectorLink">
            <param name="viewTarget">flashtimeline</param>
            <param name="popup">True</param>      
          </module> 
      </module>
      <module name="HiddenSavedSearch" layoutPanel="panel_row3_col1" group="Space Usage by user over a given time" autoRun="True">
        <param name="savedSearch">Andrew ynfs1 search</param>
        <module name="HiddenChartFormatter">
          <param name="charting.chart">pie</param>
          <module name="JobProgressIndicator">
            <module name="FlashChart">
              <param name="width">100%</param>
              <param name="height">400px</param>
             </module>
          </module>
          <module name="ViewRedirectorLink">
            <param name="viewTarget">flashtimeline</param>
            <param name="popup">True</param>      
          </module> 
        </module>
     </module>
     <module name="HiddenSavedSearch" layoutPanel="panel_row3_col2" group="Space Usage by user over a given time" autoRun="True">
       <param name="savedSearch">Andrew ynfs1 search</param>
       <module name="SimpleResultsTable"></module>
       <module name="ViewRedirectorLink">
         <param name="viewTarget">flashtimeline</param>
         <param name="popup">True</param>      
       </module> 
    </module>
  </module> 
</view>

I've been looking into timechart as I believe I have to use this command to make this happen. I also tried doing a timechart sum of Space by Username but the results didn't look right. Any ideas?