Privacy Guardian - when best to run?

I recently installed Privacy Guardian 3.2 to check it out. (Came with free registration via PC Authority magazine.) I like the look of it and it has pretty good respect in its class.

I have a question about when is best to schedule it to run -

I would have thought that the best time to run the clean would be when shutting down your system whereas It only has an option to run at Windows startup, at set intervals or on-demand. After you run the clean, it gives you options to Refresh Windows, Restart Windows or Close.

Seems there are some options that need windows to be restarted before it completes its task.

When I take the Refresh option there are several tasks in my System Tray which dissappear (presumably end)

When I take the Restart option the system effectively re-boots which is a pain and takes too long

When I take the Close option, the program closes and I can carry on BUT has it really done the clean properly given that windows has not restarted?

As I say, I would prefer to be able to schedule the job to run when I shut my system down at end of day, so I know it will be clean when I start each day.

I checked their site and the latest version V4 does not seem to have any extra scheduling options for when to run. Before I consider upgrade I'd like to understand things a little bit better.

Appreciate comment from others who may be running this product.