I generally do have:
Piccolo : 1,500,000
Freeza (3rd form) : 2,000,000
Vegeta (zenkai) : 3,000,000
Freeza final form (initially) : 3,200,000
Freeza (speed up) : 4,500,000
Goku : 4,300,000
I can make Vegeta and initial Freeza equals, too. Vegeta would have a tough time nonetheless.
It can go both ways, but I think Vegeta sees himself as a SSj due to how strong he got. He looked as his hands, like if he were feeling his own powers and deemed himself a SSj. I don't think he'd do it if he were considerably weaker. He believes himself as the SSj because he thinks of himself as the absolute peak of strength and he is in fact a monster.
As for Vegeta stating "it's not possible this is happening... I'm a SSJ!!!", I don't think it shows he was delusional or putting his entire faith on the fact he thought of himself as a SSj. Rather, it shows that he doesn't believe a SSj can lose. He even wonders for a bit "is it the best I can do? No, I'm a SSj!!". No different from the way he acted in the androids saga. He can't come to the realization ""SSJ" isn't enough. But that doesn't mean his earlier confidence came entirely from the thought he was a SSj... as his strength is what makes him believe he is.