Thats very much a personal taste issue. It depends on how you attack the strings. I like mine medium to medium low for heavy handed finger style. If you play a lot of slap, you may want want it pretty low. If you want clean deep and low then set it high like Jamerson.
Of course if you have the sloppy over hand slap technique like Mr Flea then you cant set it too low or it'll be clack clack city. Unless you like a lot of clack/buzz, which some folks do.
Again it has very little to do with anything other than YOUR preference. However most manufacturers do have specific measurements that they recommend. This will only be a guideline. Let your hands be the guide. Nobody on the interwebs can tell you what you like.
