Yes, it crimps both wings at the same time. First you crimp conductor (wire), then you crimp insulator with larger die that is close to holders.
I was looking at Engineer PA-09/20 as well, but it doesn't have separate die for crimping insulator.
Regarding width, I cannot measure it at the moment. But I always use Molex, e.g.lock header 22-11-2022 + crimp terminal connector 0008550131/0008550130 + lock housing 0009508023. Fits perfectly.
I also used it with TE Connectivity connectors which are Molex analogue.
Spritzer may seem to be very abrasive at first. But look at what he had to say about the phenomenon libratum on its thread here. He was actually quite complementary about the sound signature. And measured in his criticism of day to day design issues.
He is less measured when fan boys declare it the best thing since sliced bread. That's more on the fan boys than the headphone but may not come across was such.