Which Evo?

Hi
I wavesail in wide range of conditions. Mostly 4.7-5.7 in side on conditions. I weigh 75k and am looking at the E80. I don't sail as much as I would like and want to maximize the fun factor (and improve). I know the E75 would also work but the extra board size tells me I may just have a few more days of getting through the surf and wave riding. What difference would I expect between these boards at these sail ranges?
Thanks