My X Raven seems "dark" too but pretty pleasant during the day or night.
However, I just got the rear Sun Screen and it's just way to dark to see much of anything.
I had the rear Sun Screen on the Model 3 and it was absolutely fine, but I never found the Review Mirror "dark", actually it was a little on the bright side.
Is this normal?
Is there any user adjustment?
How can I tell it's the correct darkness?