Thanks Miguel for your comments! I am familiar with PHD2 configuration and with my AP Mach1, but not so much with the EQ6R-Pro via EQMOD. That's why I am looking for some advises from more experience users like you.
Regarding the counterweights, I knew that 2 wouldn't be sufficient based on my experience with the AP Mach1. You can see in my picture all the counterweights I was using to balance the SW Esprit 100ED. When I took the picture, those counterweights were still in the position to balance the Esprit. My scope is lighter than your Esprit 120ED however, it is loaded and it's also tall. I was thinking in adding one more counterweight however, I will see how my guiding is based on this configuration.
The AP Mach1 mount is for my 9.25 Edge HD (Imaging at F10 or F7). I still don't have a permanent setup and normally I have to go out of the city to get descents skies. My goal is then to take both scopes and collect all the data I can.
By the way, nice rig you have there!
Clear skies, Diego