BTT CAN Bus toolhead control board I'm going to use has three fan connectors. Two 2-pin ones, and one 4-pin. What is more valuable, to have tachometer and PWM control over the part cooling fan, or over the hotend radiator cooling fan? On one hand, better part cooling fan control can make better prints (is the 20% cooling"really a 20%?).On the other, being able to easily detect stall on a radiator cooling may be useless 99% of the time, and save my posterior this one time it's needed, by stopping heater when hotendfan fails. So I am lost here.
Most printers use only 2-pin fans so I guess it's not that big of a deal, and having either one on full control would be a progress, but I want to get the best of what I've got when I'm building it myself.