vantagesc:
Not Grant, but I'll say it depends on how fast this corner is. If you are only going 20mph and the uphill is severe, then it can feel a bit sluggish until revs get to 4.5k or above . In those situations, a downshift to 1st is worthwhile. With rev match, pretty easy to get into 1st, though it's not as easy as 2nd.
On a leisurely drive on say "The Snake" / Mulholland (you may be familar with this road), I don't really feel the need to use 1st even though the turns are super tight. But that's also because I don't use much power on such a road.
I'm thinking las flores canyon steep uphill hairpin [or piuma] 15 mph exit speed on water and or gravel over pavement -- the classic place all the pre-991 GT3's bogged down in 2nd, and the classic place that made strads and scuds so well geared and so much fun. I cant find the shift speeds for gt4 anywhere - what is redline mph in 1st gear? Im presuming one can run first to 60 mph+ then shift to 2nd around 5k like we did on the old GT3's until we got sick of it and bought another scud. I do see max torque starts at 4750 which ties with yours and Grant's liftoff mid-4's....