Perhaps a better way to divvy up high council votes would be attaching votes to strategic locations, economic power, military power, and or unique resources?
So everyone would get a basic amount of votes for being a planet, then depending on what you offer the Trust you gain additional votes. Since vannanhiem is so important to our navy that's get votes from that, Alfhiem would get votes from being a fuel producer, that sort of thing.
The cool part of this would be that we could vary the amount of votes you get for different resources. So if we really needed a naval boom we could increase the amount of votes naval resources get.