Sabra’s Bass

I have been on a mission to figure out the proper tuning for Nirvana’s version of Where Did You Sleep Last Night.  I pretty much got the tabs figured out, now if only I could get the proper tuning.  As I was perusing Nirvana bass tab examples, I came across a note that said to tune it E flat,  A flat, D flat and G flat so I tried it.  It sounded so close, but just not quite right.  I will continue my mission until I find the sound I am looking for and in the mean time, comments are always welcome!