I actually spent some time looking at my fretting hand at tonight's gig. It would seem I use a baseball bat grip most of the time, switching to thumb for more intricate bits or stuff on the E string. It's not something I concisely do.
IMHO if it's comfortable, doesn't cause any stresses and allows you to play all of the notes you intend to, in the places they are supposed to be, then do what comes naturally. I've never had a bass lesson in my life and have been playing regularly for 34 years injury free. I probably have a sloppy technique. I could probably play slightly faster with training. I have fun though and get enough positive comments to stroke my ego occasionally.
Having said that, lessons are so much more accessible these days. If I was starting afresh today I'd probably have some