The Acid 80 is in practice not a lot "easier" than the EVO 75 despite having a few liters more. SO I'm not surprised you feel it is a bit redundant. If you like the EVo 75 so much, yes, the EVO 80 would provide a similar feel but feel significantly bigger. I very much doubt you would gain anything by going for the EVO 90 at your weight.
On the smaller side, The Quad71 would overlap very, very much with the EVO 75. It will be easier in high wind though. Personally I think the Quads are even more cross on friendly than the EVOs. If you get the E80 and Q71, chances are you will sell the E75.
If you want to keep the E75 too, I would rather go for the Quad66. At your weight its still an easy board to use. I think you will simply be amazed by how much easier it is to sail in high wind when you have a board in this size. With say a powered up 4.7 I don't think you will plane noticeably later with the Q66 than with the Q71 (or E75 either for that matter). The 66 is a really effective little board.