I'm continuing to tweak my model of the Milky Way based on catalogs of objects in or near the galactic plane. I found a great molecular cloud catalog described in a 2017 paper.
https://ui.adsabs.harvard.edu/abs/2017ApJ...834...57M/abstract
Although distance estimates derived from gas velocity are not as reliable as parallax, we are still dependent on them because there are very few maser parallax measurements from the southern hemisphere.
This shows the molecular cloud data and my model out to 12 kpc. Galactic centre down.

