PropertySource best practices auto vs custom

I looked at our portal and the Exchange for PropertySource modules that might have a lot of the "universal" snmp OIDs because we want to pull some in for all snmp devices. Specifically sysLocation (.1.3.6.1.2.1.1.6.0) for starters. I didn't see one so I plan to make my own. But if there is some Official PropertySource I should know about, but overlooked, let me know.

But, assuming I'll be making my own, what would be the best practices for a near-universal PropertySource (isDevice() and hasCategory("snmp"))? Should it be a custom property or an auto property?

aka mycompany.sysLocation vs auto.mycompany.sysLocation ?

On the one hand, I think custom is made for such purposes, but given that I intend to make it "universal" and given that lots of teams use custom properties however they want (so it isnt as tidy a section as it could be) my gut level desire is to make it an auto property because I know that nobody else can set that on the portal but me, so I can guarantee some consistency.

Thoughts? And thank you!