There certainly are no fail systems!
This is why drilling has been suggested.
BeanAnimal's Bar and Grill - Silent and Fail-Safe Overflow System
Coast-to-Coast Overflow | Melev's Reef
Carey really nailed it saying drill now or it is too late!
Practice on other glass.
The BRS link I offered sells drill bits and matching bulkheads for less guess work.
I have used reef octopus and cpr(along with the real old school tube overflows in the 1980's!).
I'll never run a DT tank that is not drilled again!
I have ;180 with 2 overflows,2@120 with 2 overflows each,and a 75 with 1 overflow.
Sumps make life simple,not more complicated.
Drilled tanks make them effortless almost.
I have flooded every HOB
overflow I have owned at least once!