I need more storage for my two Synology NAS'. The storage size needs to be identical as the seconday backs up the primary. Does anyone have any recommendations (based on personal experience) of shucking particular WD external drives? I need PMR/CMR drives (not SMR) and am not comfortable with taping over pins to fix power "issues" as I have read in various places. I'm looking at 4TB, 6TB and 8TB drive sizes. Can anyone help?