I've placed an order at TireChainsRUs. For the rear tires, Aquiline MPC. For the much smaller front tires, 2 link ladder chains. These smaller ones were actually on the Garden Tractor list. I've hardly seen anything better than 2 link ladder chains for these smaller wheels, though I did not start calling folks. My total was $766, somewhat more than I planned to spend but not out of range. I found the advice here compelling. I think I'm shooting a little on the high side to be more confident they work well. Losing control on the hill would be disaster, and merely having to rebuy something better would be an expensive mistake. But I didn't buy the most expensive I could find -- I rarely do.
Thank you everybody for the great help. I will follow up when I have some experience with ice and hard packed snow. And no doubt other people will use this thread, as there is definitely stuff here I didn't see in the several other threads I dug up here!
Tips I wish I had figured out earlier: I wish I had learned the categories and descriptions first: 2 and 4 link, ladder, duo (or H), V-bar, double ring, and studded. Then I wish I had had the table at
Tractor Tire Chains-Comparison-Application to aim me in the right direction. Finally, with my three number tire sizes, I wish I had known to try searching by the last number (rim size) first and then the others, as some web sites are organized that way and all sites seem to work OK with that approach.
Thanks everybody! Keep it coming, this is good stuff to have online!