...Considerable changes can be made to the plates by judicious exposure to natural sunlight. It might be worth trying to adjust low areas of a plate by shielding the good areas and only exposing the too low areas to sunlight, until they match the rest of the plate. ...I have discovered that four hours of direct sunlight (outdoors) and another six hours of bright but indirect sunlight will raise the plate frequency by 3.8HZ each day (even on a cloudy day) ...You can cover areas you do not want to increase with a piece of aluminum foil, bent into position or lightly taped in place.
					...Here is a graphic example of the possible effects of U.V. light. Both top plates are made of the same wood; both started out just as white as the one on the right. This probably represents two weeks in my U.V. exposure box. The plate frequency increases up to a point and this phenomenon can be used to adjust plate frequencies without taking anything apart.
		...Try for an even top plate frequency of 322 HZ and an even back plate frequency of 353.5 HZ. I think you be pleased with the results...