One more thing. An easy way to check for warps is to attach a straight stick to each wing toward the tips and parallel to the fuselage. A rubber band will hold it. Then put the plane down and stand back looking at it from the side. If the sticks are at different angles you have a warp. I check my models this way before a maiden flight.

But if the plane glided straight with the rudder straight, then you don't.

Jim