I'll reiterate my opinion that the CalSci medium is basically ideal for me for road riding. It has a NACA duct in it. For me, the air hits me right above my visor, so I can ride with my visor open even at highway speeds without any issues. But with the intake vents on my helmet open, I can feel the air flowing through nicely. For reference, I'm 5'11" with a 33" inseam. I think Lomax recently ordered the medium so I would be interested to hear his opinion as he is probably closer to your height. I think that CalSci has the aerodynamics figured out. I agree with you--for you, maybe the best choice would be to cut down the medium about 2".