Mikey is hopefully going to come around and let you know particulars, he and a couple other guys here are well versed in fiberglass.
But I think what it will come down to is to simply cut and fit the parts, the cuts will be beveled and the surrounding areas ground clean. Clamp the parts in place, you could hole them with metal straps and screws I guess. Then fiberglass resin and mat over the seams and let cure. Sand it to contour and finish it in Everglass filler and regular filler for the final work. Then polyester primer is my fav on fiberglass.