I am also 5'10"..I bought the dark tinted 13" from Cee Baileys and it is perfect for me. But I am also longer in the torso and have shorter legs. I can still see over the top of the shield just fine. For me, I think the 11" would be too short and I would still catch a lot of the wind buffeting....but thats my opinion.
Depending on what type of helmet you wear and what you tolerance is for turbulence I would suggest either the 13" or 15" CeeBailey which you will look through, the equivalent Jurock or the Gusstofson +4" flip. Without the flip any shield you can look over will throw a lot of dirty air onto the top of your head so if you wear a large helmet expect to get your head bobbed around a lot.