The best way to do a wire tunnel in a foam wing is to insert a 4-40 rod as a guide right to the servo cutout. Then take an alum tube etc. around 3/8" diameter, heat it real hot and slide it onto and down the "guide" 4-40 rod. Melts a perfect circle channel right to your servo pocket....best thing about it is that it seals the foam as it goes so there are no "flakes" to tear loose. I used to have the .40 Dragon Lady-my 3rd plane and I loved it. Finally sold it though I wish I still had it. Shame they quit making them!