Seems like you've designed it so that stellar.org gets the bulk of the coins.
The calculation should be a percent of BTC that are used to claim Lumens is what should be used, not the percentage of the total BTC population. I expect less than 10% of BTC will be used to claim Lumen which means stellar.org will get 90% of the 3 billion.
We'll have to see how the initial round goes. that's one reason we're doing it in multiple rounds rather than all at once. The method may change on the next one.