I also fitted wires to my 1:5 scale Ryan PT20, but as they were only for show I did the following:
Bend four thin brass tubes to the correct angle and glue through fuselage just above the struts. (see the drawing and photo of the real one)
Using plastic coated fishing trace fabricate four landing wires. Pass them through the brass tubes and connect each pair to a stiff spring inside the fuselage.
Crimp a small hook onto the outer ends. The wires can then be tensioned and hooked over a small screw on the wing.
Looks scale, keeps wires tight yet are very easily and quickly removed when dismantling the wing. (the brass tubes can be made to look like cable end connectors)
On the outer ends I have used small plastic coffee spoons as cable end covers. Painted to the correct colour they look quite scale.