I've done a boatload of research for my personal preferences, and DivKid's and Mylar Melodies' videos on YouTube have been invaluable for helping me decide what would work best for my rack. The beauty of this whole thing becomes apparent when interactions happen. You might make a few mistakes on your way there, and your path might change. I've mentioned before that I only bought a few modules from my original plan due to my ongoing research. It's part of the fun, but can be very expensive for sure.
Check out this video for a module demo from DivKid that is incredible for droning ambient stuff:
The more videos you watch, the more you will be able to envision how different modules will interact to achieve the results you want.