What are the standoffs that are supplied with the DEV-14150 Relay Plate? I’d like to know the material, length, overall outside dimensions, and hole diameter/thread.
https://pi-plates.com/ppbase-assembly/ has all the specs 
Thanks! This was very helpful! Would you be able to tell me if there is an issue with using metal standoffs and fasteners for the DEV-14150 instead of the nylon that is provided?