FWIW, I found that I had to modify these two event handlers:
private void webBrowser1_ProgressChanged(object sender, WebBrowserProgressChangedEventArgs e)
{
progressBar1.Value = (int)((e.CurrentProgress / e.MaximumProgress)*100); /// Multiply this ratio by 100 for full scaling
}
AND
private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{
progressBar1.Value = 0; /// Reset the progress bar
}