Wobbly versus balanced, and some insights on vibrato.
Good comments. I played the violin with a shoulder test until I was about 50. I have been playing the last 20 years without it. I still struggle a bit on fast music with keeping it from slipping. (e.g. Presto of BWV 1001. )
My major discomfort with VDS is playing the string that the finger is on I.e. finding the string level. I don’t have enough experience to say what the right approach is but I think that a certain amount of stability is important. Not rigid but not random.
I have a friend who is a virtuoso violinist. When he plays my VDS he has no problems. He knows exactly where the string is all the time. It’s a gift.