Material properties - screen

I need a piece modeled with correct thickness to come out with proper mass/weight.  I really cannot justify modeling screen exactly, so does anyone know how to put in a custom weight for a square foot of screen, and have solidworks pickup the area instead of density?  I know I can ask to not evaluate hidden objects, so I guess I could hide these pieces, and do a manual count on them.

Using SW2017.

Thx,

Shane

SolidworksGeneral