I also had issues with the chin rest that came with the violin. I did research and found that others had similar problems, with their chin landing over the tailpiece and their jaw not touching the shallow cup to the left of the tailpiece. There are several models of center mount chinrests. I hope that the Wittman you sent a link for works for you. There are others - as mentioned above, Flesch (with hump and no hump), and Berber/Ohrenform and others.  Right now I use either the Berber or a Teka (not a center mount, but works for me).  But I always have to readjust my shoulder rest, no matter what I use. It is not difficult to change a chin rest.  The Wittman I think has little screws in the bottom of the 2 clamp legs to tighten it against the body of the violin, so you need a fairly tiny screwdriver.  Other clamp models are installed and uninstalled with a special little chinrest tool. In those cases, I just used a tiny screwdriver in the holes being very careful not to poke all the way through so as not to scratch the violin.  I hope I haven't confused you. I do hope the Wittman works for you.

I got to thinking about the center chin rest. I had raised my chin rest by adding some blocks to build it higher, which I posted pictures in a different post.

I moved it to the center, over the tailpiece. What a difference it made, my left elbow falls naturally under the violin, and then some. Makes it easier to reach the G string. And I believe it does give you a straighter bow over the strings.

So far, I like it.  Also shown is the small plastic cap under the E string the luthier put on when he fit a new bridge and some other work. No need for the plastic sleeve on the string.