Reply to Mixtrack knob replacement

Hey all! I couldn't find this anywhere else on the community s, and please correct me if i missed it. I want to get a mixtrack but know i won't be able to stand the plastic knobs, so i went online and found a large selection of knobs i might want. I just have two questions:
1.) are the knobs on the mix track removable?
2.) what is the size of the shaft? would i need 6mm knobs?

if anyone has ever replaced the knobs on their mix track, i would love if you linked me to the knobs so i could find out a little more about them. Thanks everyone, cheers!