Fan Speed Control

FWC wrote:
For reference the 'classic' Fantastic Fan model 4000R draws ~ 3A on high, 2.3A on medium and 1.9A on low. Using a PWM controller, dialed in for what appears/sounds to be about the same speeds medium and low I am seeing 1.6 and 0.9A

The PWM measurements are deceiving. The fan still draws 3A during the duty cycle period. Your digital current meter is trying to average the ON periods but its sample rate is too slow to be accurate. This is called aliasing. The true average over time will be higher. No fault of your meter. It wasn't designed to accurately measure high speed pulses.

The first measurements using the "heating elements" should be accurate because this will be a steady analog signal. The "heating elements" are there to reduce current. The higher the "heating element" resistance, the lower the current.