If the min/max breakpoints are the same for the aftermarket fans as for the OEM ones, you should be using 91% or more to command 'off' (make sure the first cell in both tables is an 'off' value), and 15% or less to command full speed.
A/C Clutch status and A/C pressure (both in volts and KPA) are available channels. There are also channels for fan desired % and fan actual %, as well as fan on/off status.