Possible to toggle action based on window size?

Hey, love BTT, been using it for years, just recently moved up to Catalina, and I used to use a program called RightZoom to toggle a maximized window state when I hit Command+Shift+M, but now I'm trying to recreate this functionality in BTT, but it looks like I might be limited to using two separate keystrokes to accomplish this.

To be specific, I want Command+Shift+M to maximize the current window, or if I've previously maximized it, restore it to its old window size.

Is it possible to get both of these onto a single keystroke, or will I have to settle for two separate keystrokes?