If you want one persistent window to always popup with a hotkey:
Preferences => Profiles => (Choose or make from scratch[1]) => Keys => Configure Hotkey Window
I think that works with the Control-Command-Space binding mentioned above. I use caps lock to toggle my terminal, which required some remapping via Karabiner[2]
[1] I have a profile called "Hotkey Profile" I don't remember if I set this up myself or if iTerm did it for me. I have it configured to appear on whichever monitor my mouse is on when I open it, and to have its window fill the bottom 1/3 or so of my screen
Preferences => Profiles => (Choose or make from scratch[1]) => Keys => Configure Hotkey Window
I think that works with the Control-Command-Space binding mentioned above. I use caps lock to toggle my terminal, which required some remapping via Karabiner[2]
[1] I have a profile called "Hotkey Profile" I don't remember if I set this up myself or if iTerm did it for me. I have it configured to appear on whichever monitor my mouse is on when I open it, and to have its window fill the bottom 1/3 or so of my screen
[2] https://pqrs.org/osx/karabiner/