Yes I did, the cockpit sides are too thin and flexible to take the load. I made an aluminum backplate twice as big as the mounts to help disperse the torsional forces. If I were to do it again and had better access, I would have first fiberglassed in a 1 foot square piece of 1/4" or 1/2" marine plywood on the backside of the side panel and then installed the aluminum plate behind that so the nuts and washer won't dig into the fiberglass/wood; with the aluminum plate alone I still had quite a bit of flexing, especially when trolling large mullet or ballyhoo. Anything to stiffen the area and disperse the torsional forces will help. The problem is that there's very little space to work in between the two fiberglass vertical surfaces. Here's a rough sketch of what I would do:
Hope this helps!