I just want to add here that I do not beleive there is a reason to reinforce the toerail structure. I installed my 1" track with 1/4" bolts, washers and nylock nuts.

The shape of the fiberglass toerail creates great strength, and that is why it is shaped, as much as to keep your toes from finding the gunwale unexpectedly. The glass I drilled on #92 was approximately 1/4" thick.

There are many irregularities on the underside of this. The glass that covers the joint on #92 from the inside is not always flat against the hull. Sometimes the hole I drilled (centered on the top) is too close to the hull side and so I used a smaller size washer. When brought up tight it bends to some extent to the shape of the glass.

Forces from the sheeting cars are distributed along the track to several holes. For these reasons I do not think (though I was concerned with reinforcement before installing) that it is necessary to provide a continuous backing.

If anything I would create an epoxy fill to seat the washers on. I used this technique when reinstalling the bow chocks. Thick epoxy pushed up into the toerail followed by a 1/4" epoxy coated strip of plywood. Then drill and tighten the nut over washers on the plywood.