ZBrushCentral

how to size the grid in draw menu?

My model is too huge for 3d printing, blah.
In the draw menu there are sliders for grid size, but I don’t know what measurement increments they are.
I can use the size slider in the deformation menu, but can’t figure out the size of the grid to scale the model.
Thank you for answering all my dumb questions!
I think I’m zipping along, sculpting like a pro, then I run into some techno problem and need a left-brain person’s help.