the recommended way would be to create the sensor once on a device in PRTG, then create a device template from this, edit it with notepad.exe for example to remove all other sensors except the new custom sensor, and then run an Auto-Discovery with the new template on all other devices (that shall have the new sensor as well).
Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.