The Multi-bar is nothing compared to the round bottom of the Stone IMO
Sure you can use that but I think your better off getting familiar with cleaning and pressing a light stone first.
Then you can use the Multi bar or even Dumbbells. I think the dumbbell will probably be more similar IMO. Take a heavy DB and get your hand under the ends and practice "safely" pressing it overhead with a pause at the top.
Shouldering and Pressing has got to be your Focus.
Cause it doesn't seem worth it IMO to load a stone 5 times for 5 points, when you can shoulder it once for 5 points in less than 3 seconds.
Have you seen the Animal Pak CAGE video that I did this year when I cleaned and pressed the Slater Stone?
Use that for reference too bro.
Good luck!
HIGA MONSTER