And yes...you can mount them sideways, use 6 different sizes, aluminum rails (I wouldn't suggest it) and that's exactly why I don't go into a lot of detail about stuff like this. Don't make the mistake of over-thinking it. Keep it simple. Light, and simple. Don't add too much stuff, as the plane will get heavy, and doesn't need it. That is a THICK wing for instance, and it would take a lot to snap one. To date, I have sheeted over 200 VF3 wings alone, forgot how many V2s and before that a zillion more, and have never heard of one snapping, ever.

But if you feel you have to fill it in until the servo is darned near encapsulated, have at it, but don't let the wire bind/rub, and keep it LIGHT.

If there's a pretty open area, as far as not a lot of detail, it's because it probably doesn't matter. Again, don't try and over-think this plane. It's simple, keep it that way.

-M