Moving front spring eyes rearward

Beside being able to install larger diameter tires, advantage or dis-advantage of moving front spring eyes rearward? Whats normal or maximum amount allowed? I have read some of 3/4 or one inch. I think it would move rear hangers to a bad angle?

The shocks won't fit on the mounting points correctly as they will be angled slightly. They will also come in contact with a stock gas tank. I tried this with the mopar "oval track" springs, which have the centering pin 5/8"ish back from stock. It caused a bunch of other problems that I hadn't expected. Those springs are in a land fill now.