There are actually two wide bands on the knife. I make the upper band overlap the lower to shed water better. On the back of the knife I pass the double loop of paracord under the upper band between the two rolled up 10 oz bags. The cords pop out midway down the sheath and are tied in a knot. This way the cord is adjustable for taking the knife on and off. I should take a photo of it and post it.
I do this with alot of my "survival knives". So far I've se up my Ka-bar, Air Force Survival Knife, BK-7, and NRGS with stuff under big rubber bands. It works best on sheaths that are narrow and straight. The NRGS is perfect for it.
Place items under the rubber by rolling it back and stuffing the items in as best you can. The rubber really is tight as a drum and the stuff doesn't shift around.
I don't look at the NRGS kit as anything more than a redundant set of emergency gear I'm not likely to loose. The hardest thing to do in such a kit is incorporate any sort of shelter supplies.
Under the rubber bands on the BK-7 kit there is a space blanket wrapped in 1 meter of duct tape, treated cotton, 5 liter water bag, single edge razor, Waterproof matches, and an ACR whistle. It really makes for a compact kit. The stuff under the rubber is no thicker than the Altoids tin in the pouch.
My neck knife kit sees alot of use and if you use your head you can make them very compact. I'm trying to post other photos but I'm having a problem with image shack tonight. Mac