And, regardless of strength, I like Fred McClung's idea of putting a layer or two of cloth on the outside, just for handling purposes around the shop... Otherwise, it's kind of like a big block of Perma-Grit.
Mike I really want to stress that both the inner and outer layer of glass is required for fracture resistance and to help to resist warping. Leave them out at your own risk.
I usually put a wet coat of resin on the outside.
I dont think the rods are required unless it is a very large mold.