Hi.
So looking at the script from the link I posted, I see that the method used is kind of old and isn't really addressing just copying a single plist, more to copy an entire folder of settings, so there are much better methods to get a plist down to all accounts.
Ideally, what you want to do is place the plist file into something like a /private/tmp/ location or /private/var/plist or some such rather than into a specific account, and then copy from the tmp location to all local accounts. But, if you're certain the admin user exists on your machines and its always going to be a valid location to copy the plist from, you can do something like this.
#!/bin/sh
localUsers=$( dscl . list /Users UniqueID | awk '$2 >= 501 {print $1}' | grep -v admin )
for userName in "$localUsers"; do
cp /Users/admin/Library/Preferences/org.mypreference.plist /Users/$userName/Library/Preferences/
chown $userName /Users/$userName/Library/Preferences/org.mypreference.plist
cp /Users/admin/Library/Preferences/org.mypreference.plist /System/Library/User Template/English.lproj/Library/Preferences/
done
I didnt test this at all. Literally wrote it right into my post, so I can't be sure all the syntax is correct, etc. So please test it and see if it does what you want.
That said, is this something you're planning on deploying via Casper? Or is it for some other manual installation process? if the former, why not just use the DMG format and FEU/FUT options?
If the pkg + script method is necessary, I'd encourage you to look at some more posts here on JAMFNation as I know there are other threads that cover this in greater detail.