I would try rope 1/8 polypro camo cord. I've had fun with this cord. I have done the tricks and set a couple of World records. HITTING A TARGET AT 25 FEET. THROWING A SPINNER AT 32 FEET. I buy it on ebay. I cut the length then wash it in warm water mixed with PALMOLIVE ORIGINAL dish soap.
Is the video above the one you mentioned??
About the string do you mean paracord in camo colour, right?
Damn!!! I just bought a roll of cotton twisted string this morning!!

And last... Could you tell us more about the records???