Hey Doc, fast forward to 2:10 in this video. Gary has some excellent points on RH technique:
Yes, and while I think the other video on floating thumb has more merit, I actually think this thing with Willis is a little bit...out. No matter that he's a monster player, I've seen no other bassist play like that at all. Comparing and doing associations by hooking the fingers together and compare to piano playing isn't really the same. When playing any keys you're pushing DOWN a key. When plucking a string you're using totally different muscles. I've seen too many bass players bend their wrist for a long time and never get any fatigued, or tendonitis, carpal tunnels syndrome, or any other RSI syndrome. And still can play at speed.
As other has stressed. Play relaxed. And not struggling every note no matter how slow or convenient it is. I think every one of Scotts bass lessons, Scott angles his wrist. I think with all these different right hand techniques, it's similar to when holding a pen when you write something. I remember the days in school when looking at some classmate when writing I said "Oh, how can you hold the pen like that, don't you get cramped up in no time ?! ..." and they went "no, it feels natural to me, I would cramp up in no time if I held it like you do".
To each their own. Taking breaks, and let all fingers and wrist, and forearm rest for a while, will do more wonders, than trying to find that UTOPIC placement of hands and fingers, since no one would turn out better or worse than anything else. It's just that one think there should be something "one position fits all". There isn't. Because people are equipped differently. A very tall person would really have to use different wrist positions and fingering, as well as hanging the bass, and even when sitting down, than a very short person with short arms. On piano, where the instrument is detached from the players body, it's more easy to just adjust the chair and distance from the piano, so a tall person with long arms and a short person with short arms can "reach" the keys in the same 90 degree angle any time.