I use a 12" of 1/8 shock cord tied into a loop and tied just over my weight. when I wrap up the anchor cord I can strech out the shock cord loop and loop over the tail or head with no chance of coming loose or maring the decoy.
For anchor cord I use a tared poly cord ( never comes loose )
For anchors I use 4-5 oz wheel weights( used,free at tire stores) ,with a hole in the clip for the cord. I hunt weedy marshs and they hold great