Reboot script for Citrix server warn users first

We have Presentation Server 4.5, but not the edition where I can schedule reboots ( I assume because I don't have a Resource Manager).  I'd like to schedule reboots of the server weekly.  I see there are a couple options, shutdown.exe and tsshutdn.exe.  Are either of these better to use if I want to notify end users ahead of time before the reboot?  Say 15 minutes?  I know you can use comments with the shutdown.exe command.  I'd also like to disable logins when the 15 minutes starts or even before that.  I see there is a command to do this as well from the Windows TS side, but not sure if that translates through to Citrix.  

Here is an example of something I found and I'm not sure if it will work or not for my scenario.

change logon /disable
logevent -S W -C 7311 -e 3603 "AUTOMATED SERVER REBOOT IN 12 MINS"
msg * Please log off and save your work. Automated Scheduled Reboot. The Citrix server is going down in 12 mins.
sleep.exe 300
msg * Please log off and save your work. Automated Scheduled Reboot. The Citrix server is going down in 7 mins.
sleep.exe 240
msg * Please log off and save your work. Automated Scheduled Reboot. The Citrix server is going down in 3 mins.
sleep.exe 60
net stop lpdsvc
net stop spooler
sleep.exe 120
del c:\WINNT\System32\spool\PRINTERS\*.* /q
change logon /enable
tsshutdn 30 /DELAY:0 /REBOOT