1/ if you forget to activate approach it will do it anyway
2/ in cruise where most of these unreliable airspeed incidents have occurred you don't set 90% N1. You adopt the normal attitude and thrust your Aircraft uses for cruise.
The memory items in the QRH are for initial actions after takeoff, they then say ABOVE MSA CIRCUIT ALTITUDE LEVEL OFF FOR TROUBLESHOOTING.....
If you are in Cruise you would compete the memory items ( A/T F/D A/P off ) then skip to the last step in the table giving you the pitch attitude and thrust setting for level flight.....something you should already know anyway because you've just be looking at it for a long time....
For the A330 it's 2.5 deg and 78% N1 for most conditions.