I've tried that program that your link suggests, and in fact (contrary to the title of the article), it will not work for "Any Linux OS", instead it will do so for the list of OS's that it contains within the program (which is bountiful nonetheless, but sadly not inclusive of Zorin). I've tried to manipulate it by changing the file name of the Zorin iso (OS 5 and 4) so that it would fit if i selected a OS that was included on the list, to see if it would work - and unsurprisingly it has not.
I've done a little research into the program and apparently there might be a way to create a persistent drive from within any Linux OS by using the terminal and essentially coding a manipulation- but due to my limited terminal experience and short time on hand, I have not gone too far with success. I will try to do more work on it once I get the chance. Thanks again for your post!
Ps: If anyone comes across this with an interest to explore persistence as I am, here's the link that's brought me to what looks like could host some potential hope in (manually) creating a persistent Zorin OS.http://www.pendrivelinux.com/create-your-own-live-linux-cd-or-usb-distribution/