Hi Peter,
You can have different degrees of openness mapped to different notes. This can be set in the Settings > Midi-in/E-drums menu.
Or you can also use CC values to trigger tight, open, open 2 etc.
To manually adjust the Hi-Hat response you can go to the Settings > Midi-in/E-drums menu.
Click the tab that reads "show" > then select Hi Hat > Hi Hat Pedal CC > then select the articulations that appear > then click "Hi-Hat and Snare CC".
Please also see this video on fine tuning your hi-hat to fit your playing style (In the video, however, he's using Roland E-drums):
For instructions on how to do this using MIDI Out from the Pearl Mimic Pro we'd recommend contacting their Support to see if they can assist.