This is the video, and it shows the best way to do it in my opinion. Here he is doing it on an LC9, but except for the hammer spring (the EC9s is striker-fired and has no hammer spring) it is removed the same way.
Notes:
1) The metal disconnector is "dovetailed" and in a slot on the fire-control group (FCG) housing, and trigger must come out.
2) The trigger spring pin access hole (shown in the video) was not the way I did it (remove the pin)
3} I used a magnetic-tip pocket screwdriver and "pulled" the pin from the top after lining up the hole. Literally took half a second this way.
A way that I could not find anywhere else, and feel I may have innovated this method.
4) There are a few tiny springs that can go flying when you are working on the FCG, and I found it best to remove them first; working inside a gallon-size freezer bag
to catch jettisoned parts/springs.
5) Video author calls the magazine-disconnector a "PIN" a few times, but clearly it is a spring.
6) The entire video is useful, and should be watched in its entirety. Except for the hammer-spring it is identical mechanically.
I've started the video at the mag-disconnector removal part for a quicker determination if you want to do it...
Mag-tip pocket screwdriver. The longer the magnet the better.