Yeah. I tried that to stop the over temp notifications, but it only works for array drives I think. If I select the drive in the UD section I just get the SMART status. Managed to calm the fans down by setting them to wok with "System Temp" rather than "HDD Temperature". Not a great solution, but it will save wear and tear on the drives until the preclear is finished.
Was hoping that the plugin could be modified to ignore external drives, but my guess is that SM lumps all drive temps together.