Hi,
Thank you for posting in Symantec community.
Q.I'm currenlty using this, but I'm not really sure how often this should be run. Is it ideal for this to be run before an virtual image cloning event? Or just run it after the initial full scan?
--> After the initial full scan.
You can use the Virtual Image Exception tool on a base image before you build out your virtual machines.
As you know detail steps are given in this article: https://support.symantec.com/en_US/article.HOWTO55325.html
Also, there are some broken links in this article but now I have requested concern team to fix them ASAP.