Cool Mat. Keep the feedback coming.
Poster #10: Most 75kg EVO 75 sailors would say 5.7 is OK but sail carrying capability is rather individual so I can no say for sre how you will find this combo. I'm a few kilos lighter than you and enjoy my E80 with 5.6, 5.9 and even 5.3, but I would never choose it as my all round wave board for 4.5-5.7 without a smaller board in the quiver. That would be the 75 (or even the 70 for me and stay with 5.5 as my biggest).
The 2008 EVO 75 also has a bit faster rocker which makes it plane earlier and also handle a bigger sail a bit better. You can trim it for even better marginal 5.7 performance with a bigger fin, something like the Drake Natural 25. So overall, I think more things are in favor of the EVO 75.