When is it right to copy the Chashmoniam and go to battle with far too few soldiers?

Why did the Chashmonaim go and fight with the odds so greatly against them? Is that the correct Hishtadlus one ought to do? Should we be taking (if that was all we had) 5 warriors and walk into Gaza with that?

I heard that the Chashmonaim asked the Sanhedrin who were mattir bec. there WAS a chance in winning (though not a very positive one). On the other hand, the Sanhedrin (particularly Rabban Yochanan ben Zakai) told the Kano'im in the revolt before the churban of Bayis Sheini that it was ossur to initiate war with the Romans at that point because it was sheer suicide. (Of course, the Chochomim were right both times.) The Y'vanim were out to get our souls- that's why there was a shaila to begin with, which was answered as muttar. When they're out to kill Jews, there's a mefurish issur lav "Loi sa'amoid al dam rei'echa" which (as it says in the Chinuch and the Rishonim) that means we're required to fight to the best of our abilities, even if it's only for inyanei mamonos. That's also why the Shulchan Uruch says in Hilchos Shabbos that if the goyim come to us to demand mamon - we go out with weapons in order to kill them and stop them, even on Shabbos! Re what you wrote about Gaza: of course not, bec. ein soimchin al haneis. We need to fight with as many fighter jets, tanks, soldiers, whatever it takes to eliminate the threat against Jews. That's the army's job to tell us just how many soldiers we need etc. and that's what's koivei'a the halacha how many soldiers we need to be mesakein chas v'sholom- exactly like we're soimeich on doctors to tell us when we have to be mechalel Shabbos when it comes to dangers to our health.

When there is is a spiritual threat, we are responsible to fight. When the threat is purely physical, we can rely on Hashem.

Why should we fight if there is no chance of winning. We do not rely on Nissim. I truly do not understand why the Chashmonaim went to fight.