Is there a way to get "Spaces" set to remain on a relative display?
For anyone trying to figure this out, the fix turns out to be really simple, but you do need to pay attention when disconnecting and reconnecting the monitors.
Basically, whatever order you disconnect the monitors, then you need to reconnect them in the opposite order, making sure to give the Mac time to register each monitor, e.g.
                     Work Office
                     -----------
                ┌─────────┬─────────┐
                │  Left   │  Right  │
                │ Display │ Display │
                │ ------- │ ------- │
 Disconnect  --&gt;│ Spaces  │ Spaces  │  &lt;-- Disconnect
   SECOND       │ *set A* │ *set B* │        FIRST
                ├─────────┴─────────┤        &amp; then
                │  MacBook Display  │   take a 1-2 second
                │   Spaces set C    │        pause
                └───────────────────┘

                     Home Office
                     -----------
                ┌─────────┬─────────┐
                │  Left   │  Right  │
                │ Display │ Display │
                │ ------- │ ------- │
  Reconnect --&gt; │ Spaces  │ Spaces  │  &lt;-- Reconnect 
    FIRST       │ *set A* │ *set B* │       SECOND
    &amp; then      ├─────────┴─────────┤
   wait for     │  MacBook Display  │
 anything to    │   Spaces set C    │
 be displayed   └───────────────────┘