> One thing I've observed is trying to arrange people to play board games is quite difficult because you can't predict how many people will show up. People get sick, misread the times, etc. And a lot of games are very sensitive to player count, so having 2 people too few or too many has the ability to make the game somewhat unplayable

You're trying to arrange the wrong type of event. A board game group plays a variable number of games simultaneously to accommodate the number of players each game can support. A board game group does not try to fit everyone into the same game as a matter of principle.