How about the top cover of a 25 or 50 cd stack for a cap. They already (most) have 4 holes or notches at 90 degrees. Just cut the flat top off and sticky tape your fishing line to the holes. Then you can just drop the hole thing over your dew cap and use a little blu-tack to hold it or just sticky tape?
Maybe something elastic for the difraction spikes like thin black hat elastic would work a treat for this?
cheers Gary
