Another idea is to turn it into a vise. As it is, the minimum board length is 6 inches as is for the CW machine. At least one roller must be applying pressure at all times to hold the board. I cannot, for example put a 4 inch long board in the carrier as it will have no downward force on it when it is between the rollers.

A long threaded bolt or two which squeezes the sides of the jig together could clamp the board independent of the roller pressure. The length of the board would not matter. (This would also allow boards to be slipped in and out without raising the head.)