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:

nb it looks like that works to me but I have no experience of it - 4 * gain from line level should work ok, you might want to do some further research - please report back...

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

good that's an important step...

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.

you also get crossfading with the a-138d
the 200pi will just do a basic modular to instrument (pedal) level and back
so it's a toss-up - crossfading and gain control vs 2 channels and external gain control (if needed) either from pedals or in rack

As for DAWs, I primarily use either Reaper or Studio One, but also have the light versions of Ableton and Bitwig.
-- cj18

ok bitwig handles cv natively I think, not so sure about the others - I know the full on studio version of Ableton does, but is expensive - which is why I got Logic instead (mostly just use it as a tape recorder and mixdown, but also wanted video in DAW for scoring to picture) - otherwise there are plugins - including vcv rack, that will work with the cv outs of your audio interface

"some of the best base-level info to remember can be found in Jim's sigfile" @Lugia

Utility modules are the dull polish that makes the shiny modules actually shine!!!

sound sources < sound modifiers < modulation sources < utilities