The nose is more than just a 1 piece change. Its the key starting point of an entirely different design ethos. I expect the drivers can't tell any difference because I highly doubt McLaren have done all the other changes that go with a higher nose (which includes a higher tub, which we know they don't yet have). I expect McLaren are just investigating if its worth going down that route. The nose design is far more complicated than just swapping a nose cone.
Anyway, back to today. I've not been following the practice to much, but from the times alone I have absolutely no idea who to put in my predictions....