Remote automated install of Oracle 10g client

We have a situation where we need to rationalise the range of installed Oracle clients (i.e. the bit that sits between the app and the network stack) we have installed. We currently have versions from 7.x through to 10.2 installed accross approximately 12,000 desktops (accross various locations in an area of around 26 square miles) running various apps on Windows versions from NT4 to XP (mostly Windows 2000). We are also introducing a standard TNSNAMES.ORA file (this is the impetus to standardise on a single client version as different locations on disk and formats of the TNSNAMES.ORA file would make it pretty much impossible to manage the rollout of the file otherwise).

With the number of desktops to be updated and the area they are spread over it would not be possible to do this by visiting every desktop so management are proposing automated installation of the Oracle client through scripts run at logon requiring no user interaction. Has anyone ever tried something like this? Are there any lessons learned you would be willing to share?

I haven't been able to find any references to this sort of work other than how to do a silent install using a responses file. I have looked at the 10g Instant Client which looks like it might be more suited to our needs as we just need to copy the files onto the desktop and set the path variable. Does anyone have any experience of using this client that they'd be willing to share. I have used it in test and it seemed fine, I'd be grateful for any comments or advice.

I suggested that we look at moving applications to Citrix or other thin client solutions so negating the need to have the Oracle client on the desktop but was told that this would be too expensive to consider right now.