Those bells look fab, having two sizes is a great idea.
Knees loook awesome too bro, especially with the metal bracket/clip
Mike, you are the master lol
Seeing as it needs painting then styrene would be good as it gives a cleaner pull
HIPS (High Impact Poly Styrene) is a good compromise as its very similar to ABS, but has greater UV resistancy. Again it shouldn't matter though as we'll be painting
Plus it has the giant sight box on top which would be difficult to cut off and smooth over
I don't think its gonna light up the costuming world, i'll stick to my resin clunker