I say drill two holes in the tank, then run lines to fuel dots in the top of the wings...like a real overwing fueling station. Then have an RC tankwagon full of fuel pull up alongside the plane to fill up.

But in all seriousness, if you do drill a hole in the tank, reinforce the area first. Think of a balloon....it you stick a needle in it, it'll blow. But if you put a piece of electrical tape on it, then put a needle through it..it will hold together. Maybe roughen the surface of the tank, then use some fiberglass cloth and 3 hour epoxy. The slow cure epoxies tend to be more flexible. Also, in your set up..make sure you can drain the tank throught the dot...not just fill it.

There's really only one way to find out....