Whatever makes you comfy there's world class flyers that use one or the other. Personally I use thumbs for airplanes, pinch for helis but I didnt even realize that till someone pointed it out and asked me about it. If you plan on flying thumbs with helis you will probably need more expo, but I find pinching more precise, heck I even switch to thumbs for more sticking banging type stuff like piroflips.