After messing around with the intake, my team found that the 100 RPM motor cartridges gave enough torque to push 7+ cubes into the tray, speed was not an issue. But the main problem that it sounds like you are having is a compression issue. At first my tray could only get 4 cubes, but after playing around with the compression and intake angle, we basically doubled that number of cubes that we could take in.