I use a Ride Duster helmet and it's not that bulky. It's a small and my old helmet (popular brand that I can't remember at the moment) was a medium. Try on before you buy and bring your goggles if they have big frames.
Think less about bulk and more about weight... Look at something from the sweet protection range and if you can afford it, then certainly get a carbon fibre helmet, the difference in weight is massive, i forget i am wearing a helmet with my Sweet Grimnir...
Height 5"11, Weight 200-210lbs, Born 1969
Regular Stance, Ability NOT GOOD
2012/13 114 days
2013/14 102 days
2014/15 107 days
K2 Fastplant 154, Ride DH2 158, Endeavour Vice 155, Signal OG 155, NS Evo 157 (Stolen), Flow Quantum 155