sounds like your mounts were installed wrong. i've read someone rolling the mounts forward and getting a great view. I'm gonna try the same. I've moved them forward back... in out but not rolled em yet. Right now i have a good compromise and can see behind with just a quick tuck of my right elbow.
That was me...
It amazed me the difference... because i had been tweaking the glass as far as it would go... then rolling the mount forward just a few degrees made a much bigger difference than swinging the arms forward, or tilting the glass up.
It doesn't roll much, but it doesn't need to.