whatever you do tho, do NOT fiberglass on the outside! than will ruin the piece! and if your going to glass it, wear a respirator at all times, because sanding on tat stuff is serious danger. personally i use a rondo mixture with fiberglass in it. to me its the best of both worlds. the glass gives it great strength, and it sands really well due to the body filler. just experiment with each on some scrap pieces and see which method you like the best
and im gonna agree with Psquiddy, add more detail to your weapons before you harden them!!