This is the best idea! (except for co-mingling ski parts and bike parts)I use toe straps from bicycle pedals..
Back when I had toe straps on my bike pedals, I didn't imagine a future where I had to worry about obstacles hanging below/sticking above the bases when waxing, I just had to scrape the excess wax out of the center groove.
I have a bunch of loops of parachute cord for ski-brake ties. Going shopping for something that can be made in my garage in 15 seconds? I wouldn't have thought of that.