Settings.lua of what?
ULX has nothing to do
with weapons,
or vehicles.
Not recommended, but, you could have headadmin inherit from admin group.
That would make server see them as admins, along with all admin standard Source server commands though.
You could write your own lua to check for weapon and prop spawning, but, that's beyond the scope of this section of the forums, and, it's been asked many times.
Just search using the search box from forum front page.