Are you really sure about this, have you tried them?
Here's a list of lense tint transmission in percentage for oakley a-frames and wisdoms (must be the same for corwbars). There's also a protection index. S0: very low protection. S1: light sun. S2: Normal sun. S3: strong sun.
Clear: 83% PI: S0
H.I. Blue: 81% PI: S0
H.I. Persimmon: 63% PI: S1
Persimmon: 62% PI: S1
Pink Iridium: 57% PI: S1
VR50: 50% PI: S1
G30: 30% PI: S2
Blue Iridium: 30% PI: S2
VR28: 28% PI: S2
Gold Iridium: 20% PI: S2
Black Iridium: 18% PI: S2
Fire Iridium: 16% PI: S3
Here it seems like the pink iridium is pretty allround, actually better when the sunlight is weak. Too bad they don't sell the blue irdium lense anymore, that seemed like the perfect one..