Vegeta PSSJB (Final Arc Granolah) vs Jiren (Beyond Limts)?

[SIAD]

If Vegeta wins, what is the least powerful form Vegeta needs to win?

 

[Goku9001]

Vegeta wins. Blue Goku at the beginning of the Granolah Arc was able to fight against Granolah's clone who was serious since he was powered up with an aura. Goku and Vegeta believed Granolah was the strongest of the universe and had no suspicions of Granolah when Goku fought his clone. It's only when Granolah's power hadn't dropped at all that Vegeta started to have become suspicious.

Weakest form? No idea. We don't have enough information on that.