My head is a bit of a weird shape too. The helmet is tight to pull on and off which was supposedly a good sign, as it doesn't just slide on with no resistance. Side to side and back to front movement is minimal. My eye line is centred in the visor. My cheeks move with the padding of the helmet, and I can slightly feel the inside of my cheeks when I make a biting motion. These were all things I have heard from multiple sources are signs of good fit.
The thing that slightly concerned me was that when I put pressure on the back of the helmet, when pushing it forward (with quite a bit of force) it nearly covers my eyes. That's to say if (god forbid) I were to come off and the helmet got caught on the chin guard (forcing it down), the brow of the helmet could nearly touch the bridge of my nose, although the back of my head never becomes exposed.
However, I feel like a smaller size (XS) would just squeeze my eyes out of my head. So I got thinking is there really going to be a helmet that ticks every box? Surely most people, or at least people with weird head shapes, must make some concessions when choosing a helmet.