If you go with the silicone it will only make the job much harder to do properly when you find out it doesn't work. The leather you have in there will allow the hull/beam joint to move already. Go with thickened resin! If you are worried about the cosmetics there is pigment available for either resin, and it is in the beam box anyway so you only see a small amount around the edge. A mornings work if you have the materials to hand. As stated in earlier post this should be done regardless of whatever else you try. Don't forget that if there is play there it will lead to fatigue. A stiff platform is also more responsive.

Cheshirecatman