Getting concurrent users from SharePoint's RequestUsage SQL view

I've been curious about how our SharePoint farm is faring.  One of the statistics that is interesting to me is concurrent users - the number of users that the service can provide at any one time.  There are various methodologies behind this, but the one I opted to use was to look at how many unique users are accessing the site in a ten minute period.  It's not a 100% accurate determination of concurrency, but I didn't want to purchase additional software to do some analytics, and the SharePoint web analytics just wasn't cutting it for me.

First, I enabled Usage and Health Reporting (from Central Administration / Monitoring / Configure usage and health data collection), with the important event being Page Requests.  Enabling this will create a new database, typically named WSS_Logging, and a few SQL views to perform selects on this data.

Next, I used the following SQL.  I wanted to grab data for a one-week period.  Here's what I came up with:

SELECT 
MIN([LogTime]) AS 'From', 
MAX([LogTime]) AS 'To', 
COUNT([LogTime]) AS 'Total', 
COUNT(DISTINCT [UserLogin]) AS 'Unique'
FROM [WSS_Logging].[dbo].[RequestUsage]
WHERE LogTime < '2012-09-24 00:00:00.000' 
AND LogTime > '2012-09-17 00:00:00.000'
AND UserLogin != 'DOMAIN\AppPool'
AND UserLogin != 'SHAREPOINT\system'
AND UserLogin != 'DOMAIN\spfarmacc'
AND UserLogin != 'DOMAIN\ServFarmAcc'
AND UserLogin NOT LIKE '0#%'
AND UserLogin != ''
AND BytesConsumed > 0
GROUP BY
DATEPART(YEAR, [LogTime]),
DATEPART(MONTH, [LogTime]),
DATEPART(DAY, [LogTime]),
DATEPART(HOUR, [LogTime]),
(DATEPART(MINUTE, [LogTime]) / 10)

I realise there are probably better ways of doing this, but I'm no SQL expert. This will show a From and To datetime, a Total count of all applicable page requests, and a Unique count of unique user accounts within that Total. Therefore, the Unique column shows how many concurrent users were active during the times shown in From and To.