flipping front spring hanger to lower rear.

I have done it many times - you can just elongate two of the holes diagonally opposite each other. ie upper outer and lower inner and you can just flip it back over if you want to raise the car back up with the two locating holes still in the factory position.
In Aussie A body which I would believe use the same hangars it lowers the car about 2 inches? and changes the instant centre of the car.
Someone who knows more about suspension can explain what that means in more detail.