Given this, would I implement a Data Retrieval plugin to automate the daily import of a stock data text file ?
It's quite easy to handle this. I made my own data retrieval plugin (which pulls data from my in-house database). Then I made a simple bat file, which runs RightEdge with command line parameters to download fresh data and run a few automated systems. Set the Windows Task Scheduler to automatically run the bat file every morning, and you're done.