I use all of them, because I like to vary the tones as I deem fit. While I have learnt and do use them in an orthodox manner, I seem to have naturally developed a hybrid technique where it looks more like classical guitar than typical bass, my fingers are often bent toward my palm but relaxed, I may pluck the string with my thumb or any of the four fingers, I may use double thumbing, Index fingernail, palm mute and pluck or slap. I find the position enables shifting in and out of different techniques far quicker and easier that I can use tonal shift to alter the way the phrasing sounds.