It really depends on how the developer coded the extension as to whether adjusting the scroll width option in the module would produce the desired result or whether you'd need CSS. Same goes for the Scroll Line Character.
Give this a try. Go to your menu manager and create a "hidden menu" (just call it that). Within the newly created menu create a copy of your menu item that you're currently working on. Then go to module manager, and create a copy of the module in module manager and assign it to the menu item that you just created.