Abstract: A material-supporting cartridge comprises a frame having an upper surface with an opening, and a pin removably positioned in the opening in a first orientation with a first end of the pin positioned in the frame and a second end of the pin positioned a first height above the upper surface. The pin is dimensioned to be removed and inserted into the opening in a second orientation with the second end of the pin positioned in the frame and the first end of the pin positioned a second height above the upper surface, the first height being greater than the second height. The frame further includes a support tube dimensioned to receive the pin in each of the first and second orientations. The material-supporting cartridge can be used with a rack that defines multiple stacked rows having a vertical spacing between adjacent rows, the vertical spacing being greater than the second height.