Can't decide which I 'need' more. I fish a lot during the summer, from sun up till about 2 or 3 when the sun is brightest. I have a pair of polarized G30s that i was going to use, but I can't stop looking at the Prizm lenses. I think my G30s would be very comparable to the shallow lens as far as light transmission, so I am leaning toward the Deep Water lenses. Is the only difference between the shallow and deep the percentage of light transmission (I believe the deep is 10% and shallow is 21%... ), or are there other differences? Or should I just buy both (j/k can't afford both...).