Vegeta is a little stronger. Zarbon took more damage from Vegeta's hits even with the dirty tactics and I don't see Vegeta putting a whole hand through Zarbon's torso just because he was a little off guard if they were equal, this isn't Super
I don't think Vegeta would have had that level of confidence if he was weaker than Zarbon, even if only minimally. He used dirty tactics to avoid a lengthy drawn out fight, but it never seemed like Vegeta thought that was his only chance to win.
I place him at 27k personally. Vegeta getting scared at the initial transformation would reduce his Yūki as what happened with Cui. Scared Vegeta would be 16k I think. Scared Cui at 12k.