toelie888, sorry, I can't help you out with an answer to your question just yet, but I wondered if you could elaborate on things for the benefit of my simple mind?
I too have the same setup, with Essentials, so can't do live storage vMotion. I also have production servers on ISCSI datastores, and some other servers on "cheap" NAS boxes, that are NFS stores. So I could test your theory, but I just need to know the steps in a bit more detail. What do you mean by "punching zeros"? What are you doing in detail to achieve this?
I need to do this very soon, so I can let you know my findings, but please educate me 
Many thanks, Alan