Players would be the leaders of the two main factions plus a couple of other key protagonists (notably the catholic Duke of Gordon who was constable of Edinburgh Castle).
There is a four player version with one umpire that doesn't worry about the rabble rousing in the streets overmuch. It focusses on the deals being made in the Convention and the efforts of John Graham of Claverhouse, 1st Viscount Dundee to keep the Duke of Gordon in possession of the Castle in the face of the Duke of Hamilton's efforts to evict him.
A slightly expanded version would have six or eight players and two umpires. This would model the rabble rousing outside the Convention as well as all the bits the smaller version would cover.
The game is about trying to persuade a number of undecided members of the Convention to vote the correct way. There should be several ways to achieve this including stirring up public support; private persuasion; speeches in the convention; bribery; patronage; physical intimidation.
Some aspects might use a modified form of Jim's ''Lambent Meteors“ rules (working over several days rather than the space of an hour or two). Other bits need a mechanism to swiftly resolve inter-faction violence. Both need tracked as public opinion.
The NPC convention members will be tracked using playing cards. Red for James, Black for William. The value of the card being the strength of support. Cards should be played face down by the umpire on a 5 lane grid. Before each card is placed the umpire should roll 1d6 and subtract the result from the value of the card.
0 to 2 goes in the middle (neutral) lane. 3 to 5 in the lukewarm support lane (4 or 2 depending on faction) 6+ in the outer (strong support) lane a negative result is treated as if the card was of the other colour.
Position in a lane does not affect the outcome if a vote is called to depose King James VII. What it represents is how those NPCs appear when they speak publicly and how they will (most likely) vote on other matters.
Bribes and other influence is played as tokens on top of the face down card. This is taken into account along with public opinion for the final vote.