- Turn off the built-in patrolling by setting $wgUseNPPatrol, $wgUseFilePatrol and $wgUseRCPatrol to false (and anything else if necessary)
- Set only one tag with one level in FlaggedRevs (accuracy: spot checked) and remove the reviewer group
- Remove the autopatrolled and patroller groups manually (if necessary)
- Grant the stablesettings right to sysops and higher groups
- wgUseRCPatrol is false by default
- For FlaggedRevs, see here. By what you wrote, I understand you want it on NS_MAIN, $wgFlaggedRevsTags['accuracy']['levels'] as 1, unset the reviewer permission, and make the stable version not the default content for pages. What else? Check out other wikis' settings here.
@DatGuy: The FlaggedRevs settings should remain the same (i.e. it should be available in the same namespaces it's currently available in) except that you can't set multiple tags/levels, but only one. Check out the "ptwiki" configuration in flaggedrevs.php; it seems like they also use just one tag judging by the comment "We have only one tag with one level" on line 556 which is what we've opted for.
There should be no reviewer, autopatrolled and patroller groups after the change and sysops should have the "stablesettings" right.
You might want to check out T154285. It seems sort of similar to this request when it comes to "turning off native patrolling/hiding exclamation marks in favor of FlaggedRevs".