If you are going to losten the screws that hold in your retracts, go ahead and take them out and install a thin washer under the retract unit and the wood to act as a spacer. Then reinstall the screws. I had the same problem, but found that when I adjusted the length of the struts, and adjusted the toe in of the wheels so that the plane would track straight, the problem took care of itself. I wouldn't just losten up the screws and then expedt the plane to hold together under the stresses of landing and vibration off your motor.
Good Luck,
Darrell B.