FWIW, when I put an aluminum hood on my car, I just stretched the latch spring a bit to take tension off it and make it easier to close the hood. It still doesn't close as easily as the heavy steel hood did, but it sounds like that's quite common. I haven't seen any signs of galvanic corrosion on the aluminum hood, but both my hinges and the hood had good paint, so metal to metal contact is minimal.