Copper Shielding helps. I don't usually do my Pickguards, unless a Thinline Tele. They come with some attached around the Controls. Last time I used Copper, it was touching the bottom of Pickup Poles that stick out, so Bridge Pickup wasn't working. Of course I messed and re-did wiring in Cavity before finding problem? Just took a little Masking Tape over it. Problem gone!