Installer usability: improve timing of security messages

Related to http://drupal.org/node/145335. Please mark as duplicate if needed.

When I install Drupal 6 and I save the database configuration form, I get the message to change the permissions of /sites/default to something safe. Since the message is shown at the top, I change these permissions before filling out the site configuration form (which is shown right after the database configuration form).

When I save the site configuration form, Drupal tells me that /sites/default needs write permission, even though at the start of this form I was told to change the permissions to non-writeable. When I change permissions to writeable and reload the form, I'm told that Drupal is installed, but not that I should change the /sites/default to something safe again. I think this will confuse new users.

As far as I can tell, Drupal only needs to write to settings.php when the database configuration is saved - so the message (saying /sites/default needs write permissions) after saving the site configuration form is not needed?