Open the material you are using, make a copy and change the attached Vectorial hatching to the grid size you want.
You may have to make a new fill if there is not one available.
Erika
Architect, Consultant
MacBook Pro Retina, 15-inch Yosemite 2.8 GHz Intel Core i7 16 GB 1600 MHz DDR3
Mac OSX 10.11.1
AC5-18
Onuma System
"Implementing Successful Building Information Modeling"