More important question would be - lets clearly define how much damage Green Kryptonite can do to Superman. It has never been consistent, in Donner movies (STM, S2) it makes him weak and turns him into jelly, in SR it poisoned him and weakened him so that he could be hurt.
Now this is going to be controversial, but it's a thought I've had a long time to think about.
1. Kryptonite was created back when Superman lacked challenging enemies to fight. These days, he has more than enough challenging enemies of equal or greater power.
2. It's too easy and obvious of a plot device. You want to look me in the eyes and disagree?
3. It's a single aspect of the mythos. Superman as a character can exist independently from kryptonite.
Get rid of it. Do away with kryptonite.