Your mission, if you choose to accept it, is to produce a scenario in which the Estates-General, convened in 1789, is able to conduct the business with which it was assigned. You are permitted to adjust with the general details as you see fit to a modest degree, if needed (such as the year in which it is convened). Ideally, the result should include a continuation in some form of the traditional three estates.
For starters, my humble proposal is that the debate over whether to vote by order or by head be answered with a simple: Oui. All votes will be counted by both, and require both a majority of the individual delegates and a majority of the orders as a whole. Since the Third Estate had won their desired increase in representation (they, in fact, outnumbered the first two Estates combined), the would have a voice in the affairs of estate, while simultaneously still protecting the prerogatives of the first two Estates.
For starters, my humble proposal is that the debate over whether to vote by order or by head be answered with a simple: Oui. All votes will be counted by both, and require both a majority of the individual delegates and a majority of the orders as a whole. Since the Third Estate had won their desired increase in representation (they, in fact, outnumbered the first two Estates combined), the would have a voice in the affairs of estate, while simultaneously still protecting the prerogatives of the first two Estates.