I think it was 4% chance of a rare off the 1k list for the 1k gamble, 4% chance for a rare off the 10k list and 8% chance off the 1k list for the 10k gamble, and 4% off the 100k list, 8% off the 10k list, and 12% off the 1k list for the 100k gamble. So if you want an item off the 1k list, the 1k gambles are the best way to get it.