I flushed the pan with 4 quarts of spare oil I had sitting around doing nothing and it came out with some glitter as well, so I put it to good use.
I had to order a Subaru filter and crush washer from Amazon yesterday as my dealer parts department seemed to think it was okay to close at 1pm on Saturdays - eeek. As I was waiting for it to arrive today, I had the car draining all day yesterday and a long time today, about 24 hours. The owner's manual stipulated that it took 5.3 quarts including the filter. I put in 5 quarts at first and it was at the bottom of the low level mark. I put in a 6th quart and it was just below the upper fill mark. I then put in about .25 quarts. In all I got 6.25 quarts into the engine, far more than I expected, glad that I had some spare bottles on hand. I don't know if the long drain caused me to get more oil out of it than what typically happens. I was so afraid to overfill it going by the specs, but the dipstick can't really lie ?
The new Amsoil 5w20 feels very smooth, pretty sure it has more viscosity than the factory fill 0w20, judging by feel and quiet smooth sensations on the initial drive.