You may want to consider adding a C41S to your setup:
https://www.cnc4pc.com/c41s-pwm-variable-speed-control-board.html
You can use this wiring diagram:
http://cnc4pc.com/Tech_Docs/JINAN2ESS.pdf
Wiring to the C41S may be a little messy. It may have been a better option to go with a C82 in the frist place:
https://www.cnc4pc.com/c82-dual-port-multifunction-board-b.html
Another option may be to add a C11G to LPT3 of the ESS: