I have a dual monitor set-up and I mod'd this clamp connector by removing the top big gear, replacing it with a angled surface to support two 90-degree small adaptors so you can attach two sets of small arms, for a total of three arms, for holding lights or whatever tickles your fancy. The two new small arms should track parallel to the angle of your two monitors.
For printing, I followed the same parameters as defined in the Multifunction Arm Mounting System.
In the photos, this mod is printed in red and is attached to the blue monitor clamp (below). The blue arm (mic) is the original small arm mount and the two orange arms attach to the new red-small arm mounts. Also angled/positioned so that the mount hardware won't conflict with each other.
This model is meant to clamp onto the monitor stand mod here:
https://www.printables.com/model/878843-clamp-mount-for-monitor-stand-pole
The author remixed this model.
Removed the top large gear, changed the rest-angle so that the top shelf is parallel to desk, and added two small adaptors to bracket the original small adaptor. The intent is to use the arm mounts for the original adaptor as a mic holder, and the two new small adaptors on the back plane to support arms for a lighting system.