There is no other way to organize a nation than to say a constituency that brings ten percent of the budget by way of taxes should control ten percent of government. No other way at all. Controlling ten percent of government is just that. It means you have ten.percent equity in decision.making and that decision making can send only five percent of revenue to your constituency. Always remember that there is no other way. Executive positions, semi executive positions and etc should be shared in the same way but anything can be agreed upon by consensus and any group should be able to leave the union at any time.
If you know your weight will determine what you get then your leaders will be more responsible. Development and higher economic activities as well as higher population will mean a bigger stake or equity in government. You do your census by yourself and report to the center.
There is no other way that I can think of