Just bought a 2007 Larson 18' bowrider. It came with a wakeboard tower. I'm seeing some very minor gel coat cracking around the tower mounts. I pulled some interior panels tonight and found that the tower mounts attach with four 1/4"-20 fasteners per mount. All that they used for backing is fender washers. So I'm thinking I need to put something more substantial in there for a backer. I'm thinking an 1/8" aluminum plate about 12" long. What should I use for filler behind the plates to take out any curvature and irregularities between the hull and the flat plate. Can anyone recommend a product that is compatible with this hull. It's a VEC boat as Larson was a Genmar company. Thanks for any help and advice you can lend me on this topic.