I'm running a very similar setup with this kind of monitor arm and it works fine for me. The challenge is that positioning the two monitors relative to each other is pretty limited because the horizontal 34" uses most of the available width. So the pillar is mounted toward the left side of my desk, the 34" is on the right arm (but central to my view) and the smaller portrait monitor is out on my left.

Also, since both monitors are attached at the same level, I found the portrait one to be mounted too high, so I got one of these to compensate: https://www.amazon.com/gp/product/B0741CFJVW