How hard would it be to put a thin spacer between the bed and the frame in just part of the bed? My truck suffered from being lower on the driver's side so I finally had spring work done last year. That made a big difference but the driver's side is still slightly lower and I think the last part is in the bed itself; particularly in the rear part of the bed. I'm thinking about something like a 3/16 inch spacer at the fartherest back mounting point then going progressively narrower towards the front of the truck. Would this even be worth trying?