My tire dealer couldn't find PS4S 265/35 R19 anywhere in Europe. Out of stock.
As I preferred not to wait for May/June release and want PS4S instead of PSS or Cup 2 for my car, I settled for PS4S 255/35 R19 front and 275/35 R19 rear to sport my 763M wheels. But also the 275/35 R19 with 100 load index is a hard find. My tire dealer found a pair somewhere in Europe for me.
About going for a 255/275 setup instead of a 245/265 setup : see the dedicated thread
here.