Regarding the foam under the pickup, I assume the screws on my Dimarzio ultra jazz 5's go into the wood of the cavity, but should they pass through the foam (or cut up mousepad in my case) or just go straight into the wood? How much padding should go under the pickups? Ing general is one piece of mousepad enough, or is more than one layer necessary? Thanks in advance. BTW.- Im pairing these Ultra jazzes with an aguilar OBP-3.