btw, I recall this thread now that I am about to develop a small roll.
the Cinestill "temperature control" device has a pompous name for a slightly modified circulator. It seems it's just a circulator with preset thermostat (38C, 20C). I don't know if temperature can be set to whatever like with a regular circulator which is then very flexible, usable for whatever process.
so, my cheap chinese or somewhere-cheap manufactured circulator (bought at the Jula swedish stores that we have also here in Norway), there set at 38C, chemicals in the sink, a thermometer on the side for checking temperature of rinse and wash water that will be used on the smaller side sink. An old Blackberry phone is the stopwatch .
Very little is required. Have done hundreds of rolls like this, never a problem.
the name "sous-vide cooker" may be frightening, but it's just a water-heating device with temperature regulation.
the oldest basic water warmer electrical device (without temperature regulation/control), the good old Tauchsieder or whatever you call it in english: