RE: evo or acid
It sounds like you've got your mind made up already, but I thought I might chime in as I'm almost your height and weight (64kgs), I tend to sail in the ocean with small waves. Oh, and I own a 05 evo70 DRam and '06 evo62 wood. I'm certainly not as good a sailor as Ola and probably won't be able to give such comprehensive answers but heres my take on it...
I have used the evo70 with a 5.8 and a 24cm fin. No problems with performance when compared to a larger board, such as my kombat 95. But you lose the turny, loose 'evo' feeling. Instead it seems to hold direction a bit longer, almost a bit sticky. With my 5.2 ezzy it feels perfect. It handles strong wind and chop suprisingly well, as Ola seaid, it doesn't tend to hold one particular line, or slice through chop, but find its own way. Its constantly moving, adjusting itself upwind, downwind, but only very slightly.
I use my evo62 with the 5.2 and its fine, takes a bit to get going, but once on the plane its nice and still has that 'evo' feeling to it. I do notice it bogs a bit more when turning then the evo70 with that combo. Dunno, it might be my clumsy feet. My favourite sail size is a 4.75 with that board. I hardly get to use it with my 4.0 and those days are pretty rare here.
I don't think you can go wrong with the evo70. Even though the evo62 is really amazing, the evo70 is my favourite board, it makes your sailing better as everything so easy.