you cant always say a discharge cutoff.
if you use a 30amp dscharger then this could take the pack down to 5.4volts, but then if u took the pack and put it on a 1 amp discharger it would probably read 7 volts. It depends on the IR of the cell.
A good pack in good condition will read the narrowest range of volts. E.g. 5.4V@30amp 5.8v@1amp.
As for the cutoff, i discharge my cells to 5.4@30amp. the lower you discharge your cells the more punch and less runtime u get.
i would not advice to discharge to 5.4 for storage. And would try to equalise the cells ever 5 to 10 runs. All packs get "out of sink" sooner or later