Electric trailer brakes uneven drag around rotation

It took me 1000 miles for new brakes to reach maximum effectiveness. The "bedding in" process is because of the kind of friction material used in recent years. It needs to deposit a film on the drum surfaces as well as wear to conform to the drum. What I have noticed is that the controller has to be turned up way too high to get even marginal braking. Now with the high setting the magnets, that have yet to mate to the armatures, are overworked and galling is likely.