Permissions on Safari Plist

Question

I am trying to accomplish something with the safari prefs to distribute to a mac lab. Please don't tell me to image the machine, I already am aware of that solution.
After experimentaion I have found out to set bookmarks and home pages to what I want for all the computers in the lab by copying the appropriate plist files. What I want to be able to do is set the permission so that the user using safari will NOT BE ABLE TO ADD a bookmark or change the home page. What is interesting is that I use ARD and log off the user so that when I copy the plist files over to the clients as the owner and others can only read which is what I thought would work, but it does not work. The file still gets written out to the Bookmarks.plist. I have tried everything I can think of to allow only read only. what I really want is either someone who has already acoomplished this and is willing to explain to me the steps they did or what also would be nice is an article about these particular plist files and their relationship to each other. I know com.apple.inetconfig.plist and com.apple.inetconfigpriv.plist have a relationship. So any help would be appreciated.
Com.apple.inetconfigpriv.plist
Com.apple.inetconfig.plist
Both of these files contain information about the home page. If you remove both of them the home page reverts back to apples home page without creating the com.apple.inetconfig.plist file, but it does create the com.apple.inetconfigpriv.plist file which drives the apple home page startup. If you modify this file to reflect the home page you want then it will startup with that page instead of apples. When the user chooses the home page under preferences this file is created with the home page information. The home page is apparently stored in two different places.
Bookmarks.plist: all bookmarks
This file contains all of the bookmarks, by changing this file and copying it to the Users {shortname direcgtory} the safari browser will come up with only the bookmarks in this file.
Com.apple.safari.plist
This file contains Boolean variables that determine if the IE or Netscape bookmarks should be imported and which tools are on the toolbar of the safari browser

Answer 1

Back up all data before proceeding.
Triple-click anywhere in the line below on this page to select it, then copy it to the Clipboard by pressing the key combination command-C:
~/Library/Safari/Bookmarks.plist
Quit Safari.
Select
          Go ▹ Go to Folder
from the Finder menu bar. Paste into the text box that opens by pressing command-V, then press return.
A folder window should open with a file named "Bookmarks.plist" selected. Move the selected file to the Desktop, leaving the folder open.
Relaunch Safari. It will open with the default set of bookmarks. Delete them all. Select
          File ▹ Import from... (or Import Bookmarks...)
from the Safari menu bar. Import from the bookmarks file you moved to the Desktop. Arrange the bookmarks as you wish.
If Safari now performs normally, you can delete the old bookmarks file. Otherwise, quit Safari again and put back the file you moved, replacing the newer one with the same name. Close the Finder window and post your results.