I use to have some aluminum flat stock that had a rubber seal on one side i got off a job site but couldn't find it . I was thinking it might be able to be installed with the rubber side up and it would be able to be bent around the corners. Looks like you got it with the metal you have . I'm not super familiar with the d4 or what under the metal that you would want to look at for service was my only thought . On another note how many house batteries and starting are you running ?