The Super Whiz Kid was designed around foam wings and stabilizers which were available at the time. The plan shows balsa structure for both the stabilizer and wing, and my short kit includes the ribs to build them. Note that the plan shows a stabilizer built with sticks, then sanded to airfoil shape. (Also note that the stabilizer is shown the wrong size and will not fit correctly in the stabilizer saddle.) You can build it from sticks only, or you can use the airfoil shaped ribs included in the kit.
My stabilizer ribs are intended for use with 1/8″ square spars, 3/16″ balsa leading edge, and 3/32″ x 1/8″ trailing edge. Then the stabilizer is to be sheeted with 1/6″ balsa sheet. I suggest drawing your own plan on office paper, to make sure the stabilizer is the correct size for the stabilizer saddle.