1. Where do you want the "another variable" to be stored? Just integrate it in the js file, or make it a database field value?
Just like the size variable that now is stored in the database and relates to a particular game id this other variable should be able to affect only a particular game id. This new variable can be integrated in the JS file or the database, doesnt matter the important part is that it is related to a particular id game so you could either use it in the database or in an array at the JS file