UltraMon has been mentioned here before, though not for this use case. (Mostly wallpaper or desktop icon placement, both still surprising gaps in Windows) Even eyeballed their site before the post, and the feature isn't really mentioned.

Digging into the app, I understand why. For what I want, I'm going to need to script it quite a bit. It's doable, but I'm questioning the value of paying $40 to then require a lot of scripting time. I can buy an entire OS upgrade for half that on my hardware of choice, with the scripting interface built in.

Hopefully some other options come up in my search. Otherwise UltraMon may be it.