According to the D'Addario website the strings are very much like guitar strings. Heavy gauges with loop ends. I would not for-see any problem with breakage unless there was a flaw with the tailpiece. Nylon strings would be stretchy. All of the Bajo Sexto strings I see are steel w/ bronze, phosphor bronze, or nickel winding.
https://www.stringsbymail.com/bajo-sexto-strings-25/
https://en.wikipedia.org/wiki/Bajo_s...ion_and_tuning