Great write up. Current Valve Index user and former HTC Vive Pro user. Its been a year since I used the Vive Pro don't recall what I didn't like about it but the Vive was a step up. I do recall the sweet spot being terrible in the Vive Pro. The Index is better but lets face it I want even better.
For the most part when I put on my head set its lined up to the sweet spot. Sometimes its a little too high or low on my nose. I also noticed if its not flush to the face it can look odd at times. An example of not being flush is tight on my forehead but not tight by the nose and cheeks. This causes the lower half of the lenses being tilted away from me.
I also wish that games would offer a screen for testing to make sure your headset was adjusted properly. Something as simple the word test repeated on the screen so you can make sure your headset is on properly before you fly a sortie.