These are the settings I use on a Mac mini as a self-host server for the mobile client of Planet.
Mac mini
Several power-related settings need to be adjusted so the server can run 24x7 without sleeping. Search for "Energy" in System Settings and:
ON: Prevent automatic sleeping when the display is off
OFF: Put hard disk to sleep when possible
ON: Wake for network access
Tailscale
Tailscale is a wonderful software that can create a magical LAN for all your devices, no matter where they are.
I first learned about it on the blog of Brad Fitzpatrick, the creator of Memcached; he mentioned that he is leaving Google for a new startup named Tailscale.
After Tailscale is installed on your Mac mini and iPhone, you can use the Tailscale IP address (starts with 100) as the Planet server address.
Aggregation
Now, you can post content from your iPhone to your Mac mini. With Tailscale, your Mac mini is always reachable.
If you have another machine, like a laptop, running Planet, you can aggregate content from your Mac mini to your MacBook.
For example, here is a site I have on my Mac mini:
https://croptop.olivida.eth.sucks/
All of its content is aggregated into this site on my MacBook Pro:
So, conceptually, you can say that ohlife.eth is a superset.