And contrary to what you might be told, the rule of 9 does work with that engine.
The action of re-torquing head bolts is something that is needed only with some head gaskets. Often at 500 miles from first run. Unnecessary and not a good idea to do it at other times as corrosion will often mean the tightness after redoing them is not as even as it was before!
I have never head that the rule of 9 would not work with a X Flow.
On Series 1 LR if you had a copper composite head gasket you didn't need to re-torque the head but if you fitted the later thin steel head gasket you definitely did or you got a failure.
