I agree with MIB...
As I have always understood it, and according to our Ops manual, at the briefing stage the TAF is “controlling”...... and I’ve never seen forecast RVRs.
At the briefing/planning dispatch stage any METARS you see might be half a day old by the time you are setting up for the Approach so in Longhaul at least they are almost irrelevant, though I appreciate there will be a different emphasis on shorthaul.
In flight METARS/reported actual weather comes into play.....As for “shooting” an ILS....the reported RVRS only are controlling.