I've got a 30cc and mine flies great. I did notice the yawing at first when flying straight but after reading the thread I made sure the wheel pants were aligned and things got better. When I fly I am always using rudder for every turn no matter what plane I'm flying. Of course when I started flying RC I was only using ailerons to turn like most but when I got interested in 3D flying I forced myself do coordinated turns so now I don't even think about it. I also have a full scale decathlon and, again, you have to use rudder to turn. If you don't it feels all sorts of weird.
If you're not using rudder this airplane will probably not fly well for you for the reason discussed above