Your layout isn't large. There may be a cheaper way to go. How many operators will you have?
For a layout your size and I'm surmising that you won't be having operating sessions with lots of operators, it is fine to break your layout into the sections you suggest, but rather than using electronic circuit breakers, just use a toggle switch to kill the power to each section.
If you are a sole or couple of operators, when a train stops, it will probably be obvious where the problem occurred and you can solve it. If not, start turning off sections until the problem goes away - you only have 6 max to turn off. Not a big deal. The last switch you turned off will tell you what section your problem is in and you can fix it.
Wiring For DCC