The material settings are greyed out because to be able to edit that half of the settings, you have to expand the 0.4 nozzle drop down, then the same for a layer height, then choose a print speed setting under that layer height. This will allow you to edit these settings.
I would strongly suggest that you increase the overlap value at the bottom for all your hard plastic materials to 0.4. This ensures the prints don’t have gaps around the printed perimeters like we have been struggling with untill the addition of that box in the material editor of UP Studio recently.
And for your reference and everyone else’s, the ‘Withdraw’ box is the retraction value. 20, which is the default for most materials in the editor, corresponds to 2.0mm, not 20mm for those who found them selves confused.
With PLA there’s a good chance you’ll need to increase this value to 40 to get less stringing on your parts, depending on what extrusion temperature you decide on.