I would imagine everyone experiences wing rock to some degree. Every plane I've owned UCD, Funtana, Sukoi and now my EF 88" Yak had or has some wing rock. I was just working with my Yak today on harriers and it is my opinion the wind has a lot to do with it. Heading into the wind when the wind was blowing maybe around 10 MPH or less wing rock was minimal. When the wind died down wing rock increased. I added some power it stopped or was minimized. More power put me in a higher alpha but it did help. I agree with the previous statements CG has a bearing, and if your CG is where the manufacture suggested you may add some weight but a little at a time. A final comment or thought, wing loading probably has a bearing on it. If your plane is heavy, once wing rock starts it may continue to get worse. Remember not to correct with your ailerons you will only chase the problem. Use the rudder only to steer.
K.O.