Dual Z and Y axis and end stops on Ramps 1.4 - Merlin 1.1.9 (no replies)

Hi,

This is probably a very dumb question but I haven't been able to find a solution online for it.
I have built a gantry based on this paper [www.researchgate.net]
I am trying to modify the gantry by adding 2 more endstops, and the Marlin firmware (V1.1.9) to achieve 2 dual Z and Y axis, both with dual endstops.
I have successfuly managed to add the secondary Y axis and endstop using the modifications below:

configuration.h
---------------

#define MOTHERBOARD BOARD_RAMPS_14_EFB --> #define MOTHERBOARD BOARD_RAMPS_14_EEB

//#define USE_YMIN_PLUG --> #define USE_YMIN_PLUG


configuration_sdv.h
-------------------
//#define Y_DUAL_ENDSTOPS --> #define Y_DUAL_ENDSTOPS
#define Y2_USE_ENDSTOP _YMAX_ --> #define Y2_USE_ENDSTOP _YMIN_

However, whenever I try to enable

Z_DUAL_STEPPER_DRIVERS

I get the error

"Z_DUAL_STEPPER_DRIVERS requires Z2 pins (and an extra E plug)."

I understand that I need to plug the Z2 driver into E0 but I am not sure how to associate E0 with Z2.
I have attached my configuration files (without the Y2 and Z2 modifications).
I would really appreciate some guidance :)