I'm puzzled by the config. If I disable set home only on foundation, then players are allow to set home everywhere literally even at oil rig.

What's the best config setting for players to allow them to set home at their bases, on any floor or foundation instead of just Strict Foundation checking them?

To stop players from setting homes everywhere, you must enable this:

    "Force On Top Of Foundation": true,

To allow them to set homes on higher floors:

    "Allow Above Foundation": true,

And you can disable Strict Foundation Check.