I am not familiar with this kit, but have an idea which may work. If the wing is drilled first for the alignment dowel, do not install the dowel but buy a "dowel center" in the size you need at the local lumberyard or hardware store. This little device costs a buck or less - has a small flange which fits in the dowel hole and a sharp centering point. Simply line up the wing properly and push into the fuse - the dowel centre will leave an impression point in the fuse side which is the exact centre of the dowel hole in the wing. Finishing carpenters use these devices to mate pieces together for dowelling glue joints.