Sorry for the late join.
I spent 1/2 hour skimming this thread as I am a longtime subaru caretaker and
somewhat interested in a new BRZ or GR86.
Has the OP picked and installed a eurospec 30 grade lubricant yet?
You can hand-ring all day long - try one!
p.s: as
@kschachn pointed out, you don't need a 0W. Irrelevant. And sometime the 0W makes a compromise elsewhere.
p.p.s: I would also endoscope the oil pickup for form-a-gasket blockage, if you can get there on that engine
Enjoy the car!
final thought. You know what, I bet the Genuine Idemitsu Subaru 5W30 would be all you need - and how could they complain!