How can I keep the same desktop arrangement on two different multi-monitor setups?
I have a similar setup and now that I'm thinking about this, using Spaces is the key.


Go to System Preferences > Mission Control
Enable "Displays have separate spaces"
In the Dock, right-click (or option-click) an app.
Under Options, assign that app to the appropriate space and display.


I'm currently at home where I only have a single external monitor but it is working. 

Apps assigned to the monitor are on the monitor. I unplug it and the apps all go on the laptop. When I plug the monitor back in again, regardless of port, they appear on the external monitor.