Yes there is more to it. Motor diameter and length play a part as well. If you notice, the motor I suggested is a little larger then the one you have. Typically for sport flying you want 100 watts per pound of airplane provided and this is also important that the airplane wing loading is not over 20oz per square foot. The wing loading is quite important, more then overall airplane weight. For sport flying we are finding that lower KV motors with larger props give better thrust. The airplane I fly the most has a motor that is only 220 KV but is also the battery is 10 cells. Most of the flight is done below 5,000 rpm with a 20x12 prop. The wing loading is around 18oz per square foot. If I knew more about your airplane I could narrow things down a bit better for you.