For the planes you will be flying all you need to do is butt glue the two wings together using epoxy or wood glue. The only reason to cut in spars was if the planes would be use for high speed flying over 100 mph. Most sport flying is way below that. more in the 60 / 70 mph range . So for your kind of flying you don `t have to worry about cutting in spars in your wings even with veneer skins. After you glue the wings together and it is dry use 4 inch wide 1 oz fiberglass cloth and using epoxy, glue the cloth over the joint, leading edge to trailing top and bottom. First light sand the center joint , then mix some 30 min epoxy. Add a little alcohol to thin it out to about the consistency of water . Lay the cloth nice and flat over the joint and pour the epoxy onto the glass. Use a brush to spread the epoxy from center out to the edge of the glass cloth. Don`t saturate the glass too much. Use just enough epoxy to lay the glass down. Do bottom first then top, so that the top glass over lap the bottom about 1/4 inch . When you glass the bottom bring the glass right to the leading edge where it start to curve, and trailing edge over lap about 1/4 inch off the edge. Same with the top. Lay the top glass 1/4 inch over where the bottom stop. The trailing edge over laps you will cut after the glue is set. You can do a second coat when the epoxy is about half way dry. The second coat is to cover the weave and feather the edge of the glass. Add less alcohol this time. Note when you add alcohol to epoxy it sets quicker. So the first batch probably will start setting after about 15 mins depending how much alcohol you add. Let the wing set over night or 3 hours if doing it during the day. Sand the joint with 320 sand paper and get rid of the ridge at the end of the glass if any. You may want to lay some masking tape along the edge of the glass before you sand so as not to sand into the veneer skin. Then just cover the wing the way you want to , Fabric or plastic film. That `s how its done for sport flying no need for spars. For that type of flying the wing will be plenty strong.