I see that Brent is working on your request, but I wanted to mention that I’ve implemented something that may address your issue. Or maybe not.
I’m updating Pax Renaissance 1st edition, and when a game starts, I must build a game deck that is based on number of players and if an expansion and/or promos are included. When you start a brand new game, a window displays over the main map. In it are checkboxes to add promos, add the expansion, and to add a 2nd edition rule as well as buttons to choose how many players are in the game. At the bottom is a “go” button. When you press it, it sets up the deck and game, and then vanishes.
Is this what you’re looking for, or am I completely off base?