After hanging in Rick's garage for a week, our soupy are looking (and starting to smell) good. The temperature up there was 38 degrees, as it probably was most of the week. The humidity in the rafters was 64%, which is actually a lot less dry than I would have guessed, and good news because the main threat now is the drying process outpacing the curing reactions (slowed by the cold). I gave them a light spritzing with water to keep the casings supple for the third time.
My two test sausages have lost about 12% of their weight through drying, which seems like a lot since a 30% reduction is the "done" target, but the rate of water loss slows a lot. They start out pretty much dripping.