+1 to the number of coils around the machine head posts.
Some basses do not have string trees to help with the breaking angle of the strings over the nut, therefore the strings will feel less taut.
Occasionally, this looseness, accompanied by other things may cause buzzing in the open position.
Increasing the number of coils around the posts will increase the breaking angle of the strings over the nut, as the strings are now pushed lower down the tuning post, much like how a string tree works.
This will aid a little in the buzzing, assuming all other aspects of the bass are set up decently. Ultimately, this is not THE solution.
I'd suggest that you try stringing up as such and see if the buzzing problem still exists. If it does, then you probably have a problem with your setup.
The neck should be as straight as possible in my opinion, but it's down to personal taste. Start with the truss rod adjustment first, then go on to the saddle height adjustments.
As a guide, always look down your neck to check that your neck is roughly straight, then do any necessary adjustments to the trussrod. make sure the adjustments are made in small increments. You don't want to break the bloody thing. After you're happy with that, you can proceed on to setting the saddle heights to your liking.
When everything is done, it's also a good idea to get your intonation set up properly too, just to make sure that your bass is more or less in tune all the way up the fretboard.
Cheers.
