Hi,
As I understand you're using material from corona material library?
If so then you have no need to adjust material scale, unless you're seeking very specific effect.
All materials from material library comes with with triplanar mapping or with correct real world size units. So most of the time you don't need to do anything to get correct scale, or you only need uvw map set to real-world map size.
But if you really wan't to see your map ir viewport, you should try enabling "show shaded material in viewport", not in material itself but in specific bitmap node.