Coloured electrical insulation tape is great for making chequerboard style racing patterns on your twinwall aircraft. Laying the tape fore-aft on a wing will enable you to use the twinwall flutes as a guide to alignment.
2. Cover the area with stripes of tape
Build up stripes of tape to the thickness of the required area laying each stripe right up to the previous one but not overlapping at all.
3. Mark the pattern on the edges of the desired area
In this example we've divided the length of each side of the area by ten and made a mark with a pen. The wing is tapered and so the chequer pattern will taper with it. It looks much better than a parallel pattern on the Evo.
4. Cut lines between corresponding marks
Using a ruler, draw a sharp knife from one mark to the corresponding mark on the opposite edge of the chequer pattern. Don't cut too deep or you may cut into the twinwall. Just enough pressure to cut through the tape.
5. Lift off the unwanted pieces of tape
Using the tip of a sharp blade, lift off every other segment of the chequerboard pattern.
6. Job done - finishing off
When all the unwanted pieces of tape are removed your chequerboard pattern will be complete. However, you can add extra solid stripes down the edges of the area to demarcate it more clearly as shown in the example below.