In case anyone is curious, the Spikes-Spider chains worked great on the 20" (Style 87 rims/Diamaris tires) setup that I have! I used them 2 weekends in a row during the recent snow storms at Mammoth Lakes, CA. Coincidentally, Mammoth has received the most snow in the lower 48 States so far this season.
Anyway, I wasn't prepared to pay $500 for a set of Spikes-Spiders. With a little patience and a lot of luck, I just happened to find someone on craigslist who was selling their set for practically nothing. For reference in case someone down the line is curious in getting a set and want to know what they look like on 20" tires, here's a couple photos.
TOTAL time to install the set on the rear tires: 1-minute (:30 on each side). Awesome!!!