Ok, great! The A-183-3 fits into the space that I have available, which is a good sign. My rack now looks like this:

EDIT: it keeps showing the old pic only, so I had to break the link:

https://www.modulargrid net/e/racks/view/1766572

I have to say, it feels a lot better than it did before. I better understand the purpose of each modules in there now.

In my searching, I also came across the ADDAC 200PI. How does that compare to the Doepfer A-138D? I am guessing that the 138D is the better option, with the attenuation and amp, versus simply having two loops available.

As for DAWs, I primarily use either Reaper or Studio One, but also have the light versions of Ableton and Bitwig.