another big head!
Hi Andy,
I suffer from the same problem. One year, I tried every make at the NEC show, and only found 3 lids that would fit (Shoei, Arai and HJC - far too tight to buy Arai/Shoei, but the HJC was ok)
I currently use Caberg Just One (flip front). They're a good fit for me, and at a hundred quid, I can afford to change it each year when it gets smelly and scratched.
Head shape is the key issue though. My head seems to be very long, so trying most full face lids means the chin-bar doesn't get past my nose. The flip front Caberg gets around this, and gives me a much better fit.
I liked the first HJC lid I had, but the second (more expensive ) model was crap - not comfortable and the vents were rubbish.
Hope this helps.
Steve.