4 chambers to 8 presses (4:8)

4 chambers make 100 kg/min of sand at full speed (4 x 25). 8 presses use 80 kg/min (8 x 10). That leaves 20 kg/min of spare sand, so the chambers run below full speed or the surplus is sold.

This ratio has no published raw dust figure. By mass balance it should be close to the stone output, since each kilogram of moonstone costs one kilogram of dust if the chamber yield is 1:1.

Asked for 160 kg/min of moonstone, the solver sizes 4 Pressure Chambers and 8 Stone Presses, with 160 kg/min of dust, 184 kW and $13,620 in total (machines, solar panels and placeholder belts). It agrees with the published ratio.