You are also doing a great job with taking your time making your gaunts, rush jobs always look kinda depressing, so your off to the right track with everything,
one material that you can use for the blades themselves is foam board, its easy to cut and doesnt give that ridgey effect like card board does, not to mention its easy to paint.
Though one thing I would be careful with is to make them to huge, and be careful wear you are swinging them, My blades didnt last 3 days at a Medium Sized con, and I wasent
doing much. =P