Hello axl1971, I believe that in this situation the best would be to use VMware converter.
I believe this community post apply to your problem: unknown
In that example, it says to copy VMDK and VMDK-flat files from server A datastore folder to Server B and then attach server B. I think it is the faster option.
VMware converter would be a good way to clone de vDisk but low on performance.
If server A doesn't need the disk any more, your best option would be to dettach the disk from server A and attach it to Server B.
NFS shared volume
Either from storage array or from the VM hosted somewhere and connected to this subnet
can i use the ovftool to copy a single virtual disk and not the other virtual disks associated with a VM