I think the poly rope/ paracord idea is the best. I have experimented with weight tubes, coated steel cable, and weed whacker line; the cable and whacker line is too noisy period and it can make your nocks pop out if they are not glued in. The weight tubes work better, and are quite adequate if you install them correctly and pinch them in enough locations that they stay put, though I still have gotten some rattle with them too in certain situations. Poly rope or paracord on the other hand, if stuffed into the arrow will stay put with no issues and zero noise. Its a good idea to invest in a grain scale in order to be precise about it. Good luck. All I can say is that when it comes to pigs, 10+ gpp and a little extra FOC are your friend.