I suppose it depends on what you are trying to do. What does the screened fill represent when compared to a non-screened fill? Do you want all fills of that type to be screened?
If you use a specific pen for your fills, you could swap to a different pen-set in certain views where that pen is a lighter shade.
Or, you could use a separate white percentage drafting fill with a transparent background overlaid onto the plan, and control it's visibility with layers.
Or, perhaps look at the renovation feature, where you can override the fill types of elements depending if the element is existing, demolished or new.
There is a little more information on this thread which you may find useful -
