Can you put Z-Stacks on the YYF grind machine?
That depends, Plastic Grind Machine, or Grind Machine 2? For the PGM, yes you can, but it can result in a horrible amount of vibe that it’s not playable. So I wouldn’t recommend doing it. If I were you, I would pick up a pair of ricestacks. They work wonders. 
I highly doubt you would on a PGM. You can on a GM.