Ding, dong <--door bell. As soon as I got done writing the above question, my SCT from China showed up. Got a plug on it right away and taped the sensor to my fermentation bucket. After a couple of minutes it settled into 19.3° C. Bucket is sitting in a tote, so I covered the tote with a towel and the temps slowly rose to 19.8° and stayed there for the last 15 minutes or so. I think that'll do perfectly. Just over 24 hours being the bucket.
This all downstairs, of course.