To start, try the initial setup in oculus. If I remember right it ask for your height. What you should put in is your height sitting down. I renumbered this problem in Iracing and I think that really helped.
Now in AH, lift your head head as high as you can trying to stay straight then hit F10 which says that. You might have to do that more than once. I mix the more precise way it was done in regular AH.