Hi there,
I have had a Tacoma acoustic/electric bass for a few years now and have evolved a way of playing it that is more like finger picking on a flat top guitar. I use my thumb mainly for the E string and my first, second and third fingers for the other three strings.This is great for African style bass playing I find.
Whether a certain method is correct or not does not really matter. Who is to decide what is correct? Sometimes, a certain technique is needed to achieve certain sounds, especially where speed is involved but apart from that, there need not be rules. It's the end result that counts.
I always think of it as a blank canvas. Whether you splat paint on or use a teeny,tiny paint brush and make really precise marks, there is always something there that didn't exist a few moments ago. Same with music. It's all about creating sounds, whichever route we use to get there.
Gordon.