It's been a long time since I had a Bingo in front of me. As I recall at least some of them had an open bay wing construction. Or, is yours fully sheeted? I like dual aileron setups myself and they have lots of advantages. That said, it sounds like you are reluctant to tear into the wing any more than necessary. On the .40 size airplane at least, the torque rode system is adequate, It has worked for many thousands of airplanes. If the torque rods and ailerons are already installed you could go with a side by side servos in the wing. One servo for each torque rod. You may give up a little precision but you can still get most of the functions (flaps, mixing, differential etc.). I think the Bingo was one of those airplanes that was kitted in at least four sizes plus an ARF. On the bigger planes it probably is just as easy to move the servos to the middle of each wing. So for making holes what I have done in the past is to use a pre-cut piece of sheet stock of consistent width ( 1/2 or 3/4 in wide) as a template for cutting out the sheeting. That will give you a clean fit when you go to replace the sheeting. Then use a burr tip in a dremel to grind just big enough of a hole in each rib to fish your servo leads through. While you have your wing open use tweezers or hemostats to fish the servo extensions through the wing. If you ever have to remove the extensions, be sure to tie a piece of string to one end before removing them and then leave the string behind as a means of fishing the new leads through the wing. Once your leads are installed then you can dress the tops of the ribs where you removed the sheet and use the new sheet stock to fill in the hole. Some people can remove a strip of wing sheeting without messing it up. I'm not one of those people. When yo replace the sheet use tite-bond or other easy sanding glue so that the surface is smooth under the covering.