The solution was to install a small heating diffuser near the work space connected to the ventilation. (treehugger.com)
Lamp rings, electric heat diffusers, and steam inhalation are other types of diffusers that use heat. (verywellhealth.com)
When the YS640 is setup traditionally (heat diffuser in place) the Variable Displacement Damper allows the pit - master some additional grate level temperature control. (yodersmokers.com)