These values specify the height of each filament layer in your print. Prints made with thinner layers will create more detailed parts with a smoother surface. By default we go with 'Normal', however, if your print exceeds the booking time we will change the settings to 'Fast'. You may request for your print to be completed with the settings of 'Extra Fine' or 'Fine'. These settings do increase the print time substantially (6 hour limitation still applies).
Fill density is a measure of how much material will be printed inside the outer shell of the object. The percentage can be modified to conserve material and speed up print times. We typically have the value set to 10%.