For making the structural repair I would use 5 or 6 oz cloth with epoxy resin. I think the only epoxy they sell is West System. Sand a taper around the crack so that the original material is paper thin at the opening and tapered back about an inch around the cracks. Start with a piece of cloth just slightly larger than the opening and lay progressively larger pieces on cloth on. The idea is to match the the taper with the progressively larger pieces of cloth so that the repair is not raised above or sunken below the original surface. In reality it never comes out perfect so you will have to sand off high spots and fill the low spots. I believe the filler from West Systems is called "Micro Light". It mixes with epoxy to make a paste that is basically "boat bondo".