How to use "highresscale" variable in the properties.txt

[TheMonkeOnTwitch]

I'm making a 2x resolution and 3x resolution templates for my friends to use (they can't have slade due to storage issues). How would I make it so when putting it into kartmaker it automatically sets the "highresscale" = 0.5 or "highresscale" = 0.333333333333333333?