I'm going to give you the benefit of the doubt and assume you will actually follow through with this.

Respect for attempting to rectify the situation, but larges premines are always bad and your proposal changes nothing.

A 500m premine, excluding your first 1440 blocks, is equivalent to 10 days of mining.  It's going to dilute the value of the coin for at least 20 days, and disincentivize miners to bother taking up the coin.  And you'll still hold double that privately, with no guarantees about you not dumping your 30 days worth of mining on everybody's head.

No matter how you spin it, a large premine punishes miners and rewards people who do nothing, which is not the foundation of a good coin.