I think we need to know more information. Are you designing your jig assuming the tail wheel is on the ground, up on a support so the top tail longeron is level, or the wing support tube is level? The last option will make the bottom surface of the wing level at least at the root but if you have added washout then not at the tip. Given the geometry of the main landing gear the fuselage angle will have an impact on the height of the wing support tube. Assuming you prop up the tail so the rear top longeron is level and if you built per plans then you should be able to figure this out yourself. For the LEU plans sheet 13 gives the height from the ground to the center of the bottom longerons at station 2. Sheet 8 gives the height of the front of the wing support tube above the bottom longerons and the height of the wing fitting above the wing support tube. Sheet 22 gives the height from the wing root fittings to the bottom of the front spar which is about the bottom of the wing. By my math about 63.5" at the root, plus dihedral and washout. A similar exercise can be for the XL.
