Some updates from a few years later. Winters have mostly been lightly frosty with the lowest temp around 23. But the past week brought 4 nights in the teens and 2 days when the high wasn't above freezing. Pics from today, a couple days after the row of 4 nights in the teens.
Opuntia (humifusa I think) and Sempervivums have no trouble.
Francesco Baldi and friends in this pot are fine but some of the Sedum kimnachii around the edge got zapped.
The S. kimnachii in this mini garden feels OK.
Francescos are OK here but K. tomentosa feels limp, and a Sedum adolphi feels all limp.
Various Sedeverias in this pot seem OK.
Everybody in this area seems OK except the bright pink one sticking up in the middle. It feels questionable.
Watch-chain Crassula didn't make it this time. Lithops feels OK.
These guys seem OK.
Sometimes the result seems capricious and arbitrary. This little patch of K. blossfeldiana got zapped to the right, is OK to the left.