I've been experimenting with different materials for a while now, this seems to work better than anything else I've tried. In the process I discovered that an ignitor will actually cut a rubber band. The downside is it also tends to start it on fireThat's a nice hookup for the nichrome. I've found that to be that hardest part.
When I built mine, Cris steered me away from heavier tether material. I have simple monofilament across a rubber band. The band end up doubled around the chute/Quark bundle.