I also have the oblong head shape. I have never found an Arai that fit properly. I just bought a shoei RF1100 that is very comfortable. My HJC before that took some break in time. I wish I had used a spoon.
I wear Shoei QWEST and don't get any "red spots"on my forehead. Maybe your helmet is too small ?!
No red spot for me but then I have a perfectly shaped head. That's part of the reason that I'm so damn good looking.
. . . and humble as a bonus !