So here's "MY IDEA" from "MY EXPERIENCE/LUCK"
1.] Choose Paper, if you win press enter upon receiving your prize.
2.]After pressing enter quickly click the paper again, and if you win repeat step1.
3.]If you lose in a round(round 3 or 4), use you're Rematch point and pick Stone.
~~This is not accurate for the others though, but works with me, hehe~~
Wish it helps you, ^^,