Streets of Willow race course.
Oh, and I'm aware that each helmet fits differently. I have an Arai head, the Shoei is too wide for me. I haven't tried an AGV or Suomy yet, so I'll have to size some of those.
Arai and Shoei both make long-oval shaped helmets.The Profile(Signet) is similar to the TZR. The RF-1000 is similarly round as the Quantum, and the Corsair and X-11 are more intermediate, with the Shoei being perhaps slightly longer, or not as wide as the Arai. i don't know which models you've tried, but the wider issue is puzzling since you are currently wearing a rounder Quantum. Maybe that is the issue there as well. Try the helmets on without the cheekpads first to see if they fit across the top of your head front to back and side to side to side, the cheeks may be the issue in the end, and can be swapped-out for thinner or thicker pieces, but it seems to be where a lot of riders "feel" the fit initially.
I think AGV is more oval with most if not all of their line, and Suomys are rounder with most if not al lof their lines available here as well. There have been some recent discussions of AGV on here recently,. and you can check some good reviews for size and shape issues on www.webbikeworld.com
. I'd say that fit can probably be somewhat inconsistent thorughout the lines of helmets depending on how many shell sizes are used and where your head falls within those considerations. You might want to check into that aspect a little too if it gets to be a real issue with more choices.