folks keep talking fit. try a couple different brands. some work better for oval shaped heads, some for rounder heads. often you can return if it doesn't fit you. the standard test is, put the helmet on, then watch Grand Tour, or Top Gear or something like that... you should be able to make it thru the show...
good luck and also a huge fan of a HANS. after doing some lemon's racing and then doing a track day in my 2002, i'm looking at roll bars HANS and real seat belts. sorta kills the "drive the family to the farmers market" thing though. one does have to make choices...