His bassist for many of his best recordings was Ranchie McLean. You might want to do some research on just what kind of gear Ranchie preferred to use. But most of it, I believe is simply that it is really easy for bass to stretch out and breathe in most reggae arrangements and productions because there's not a while lot else to get in the way.
Use flatwound strings, notch the mid freq's out of the bass, and play fingerstyle right where the neck meets the body of the bass. Use a p-bass with the tone about 1/2 the way on.
Make sure to trim your nails so there are no clicks when you play the string. Use a soft attack so that the note 'blooms' after you're done plucking.