For some reason this doesn't work anymore, I have attempted to do it in a macro with /run in front of it but it automatically resizes to default after a few seconds.
I have figured out that MainMenuBarArtFrame:SetScale(.8) works for the main menu but I haven't been able to achieve the rescale of the 2 bars on the right hand side of the screen.
Does anyone know what these bars are named/what the script would be to scale these?