Yeah, had a Mk6A as my first 'real' helmet, a year or two ago...
Anyway, I find the Mk6 is
awesome for comfort level, and I'm usually shaved so I feel any pressure on my head then
I've got an outsize helmet with the back pad pulled in tight so that it sits loose but doesn't jostle when I've got the chinstrap done up. If you're feeling the strings at the top though, try cutting a piece of foam up and sticking it over the strings.