I needed to open upspace for the servo arms and ball links to move. I used the tip Andreas gave us on putting tape on the wing surface and cutting through the tape. It worked very well. It's very easy to control the cut and the cut line stays nice and clean.

If I were to do this again, I would just cut the hatch out using the tape under the cut lines, add a couple small balsa blocks underneath to support the hatch, and then tape it back on after I was done. It would be very quick, easy, and clean.