I tune my main bass E - F.
It was strung with D’Addario Nickel Roundwounds. .100, .075, .055, .042, .032, .020 (Plain steel XLB020p).
I have restrung it, it now has Thomastik Infeld Nickel Flatwounds on it.
.100, .070, .056, .043, .033, .020 (still Plain steel XLB020p).
Either way works...